We read your photo as:

A trader bought 2 cows and 9 goats for ksh. 98,200. If she had bought 3 cows and 4 goats, she would have spent ksh. 2,200 less. Form two equations and find the cost of a cow and a goat.

Mathematics

ScanSolve AI Answer

Answers

4 parts
a

\begin{align} 2c + 9g &= 98200 \\ 3c + 4g &= 96000 \end{align}

b

Ksh 24,800\text{Ksh } 24,800

Ksh 5,400\text{Ksh } 5,400

c(i)

Ksh 132,520\text{Ksh } 132,520

c(ii)

34.95%34.95\%

Step-by-step solution

14 steps

19. A trader bought 2 cows and 9 goats for a total of ksh. 98,200. If she had bought 3 cows and 4 goats, she would have spent ksh. 2,200 less.

Part a· 3 steps

Form two equations to represent the above information.

  1. Define variables.

    Let cc be the cost of one cow in Ksh.
    Let gg be the cost of one goat in Ksh.

  2. Form the first equation.

    "A trader bought 2 cows and 9 goats for a total of ksh. 98,200."

    2c+9g=982002c + 9g = 98200
  3. Form the second equation.

    "If she had bought 3 cows and 4 goats, she would have spent ksh. 2,200 less."
    Ksh. 2,200 less than Ksh. 98,200 is 98200−2200=9600098200 - 2200 = 96000.

    3c+4g=960003c + 4g = 96000

    The two equations are:

    2c+9g=982003c+4g=96000\boxed{\begin{align*} 2c + 9g &= 98200 \\ 3c + 4g &= 96000 \end{align*}}

Part b

Ksh 24,800\text{Ksh } 24,800

Use the matrix method to determine the cost of a cow and that of a goat.

  1. Write the system of equations in matrix form.

    [2934][cg]=[9820096000]\begin{bmatrix} 2 & 9 \\ 3 & 4 \end{bmatrix} \begin{bmatrix} c \\ g \end{bmatrix} = \begin{bmatrix} 98200 \\ 96000 \end{bmatrix}
  2. Find the determinant of the coefficient matrix.

    Let A=[2934]A = \begin{bmatrix} 2 & 9 \\ 3 & 4 \end{bmatrix}.

    det(A)=(2)(4)−(9)(3)=8−27=−19\text{det}(A) = (2)(4) - (9)(3) = 8 - 27 = -19
  3. Find the inverse of the coefficient matrix.

    A−1=1det(A)[4−9−32]=1−19[4−9−32]A^{-1} = \frac{1}{\text{det}(A)} \begin{bmatrix} 4 & -9 \\ -3 & 2 \end{bmatrix} = \frac{1}{-19} \begin{bmatrix} 4 & -9 \\ -3 & 2 \end{bmatrix}
  4. Multiply the inverse matrix by the constant matrix to find cc and gg.

    [cg]=1−19[4−9−32][9820096000]\begin{bmatrix} c \\ g \end{bmatrix} = \frac{1}{-19} \begin{bmatrix} 4 & -9 \\ -3 & 2 \end{bmatrix} \begin{bmatrix} 98200 \\ 96000 \end{bmatrix} [cg]=−119[(4)(98200)+(−9)(96000)(−3)(98200)+(2)(96000)]\begin{bmatrix} c \\ g \end{bmatrix} = -\frac{1}{19} \begin{bmatrix} (4)(98200) + (-9)(96000) \\ (-3)(98200) + (2)(96000) \end{bmatrix} [cg]=−119[392800−864000−294600+192000]\begin{bmatrix} c \\ g \end{bmatrix} = -\frac{1}{19} \begin{bmatrix} 392800 - 864000 \\ -294600 + 192000 \end{bmatrix} [cg]=−119[−471200−102600]\begin{bmatrix} c \\ g \end{bmatrix} = -\frac{1}{19} \begin{bmatrix} -471200 \\ -102600 \end{bmatrix} [cg]=[−471200−19−102600−19]\begin{bmatrix} c \\ g \end{bmatrix} = \begin{bmatrix} \frac{-471200}{-19} \\ \frac{-102600}{-19} \end{bmatrix} [cg]=[248005400]\begin{bmatrix} c \\ g \end{bmatrix} = \begin{bmatrix} 24800 \\ 5400 \end{bmatrix}

    The cost of a cow is Ksh 24,800\boxed{\text{Ksh } 24,800} and the cost of a goat is Ksh 5,400\boxed{\text{Ksh } 5,400}.

Part c(i)

Ksh 132,520\text{Ksh } 132,520

Calculate the total amount of money she received.

The trader later sold the animals she had bought making a profit of 30% per cow and 40% per goat.

  1. Calculate the selling price of one cow.

    Profit on cow = 30%
    Selling Price per cow (SPcSP_c) = 24800×(1+0.30)=24800×1.30=3224024800 \times (1 + 0.30) = 24800 \times 1.30 = 32240 Ksh.

  2. Calculate the selling price of one goat.

    Profit on goat = 40%
    Selling Price per goat (SPgSP_g) = 5400×(1+0.40)=5400×1.40=75605400 \times (1 + 0.40) = 5400 \times 1.40 = 7560 Ksh.

  3. Calculate the total money received from selling 2 cows and 9 goats.

    Total received = (2×SPc)+(9×SPg)(2 \times SP_c) + (9 \times SP_g)
    Total received = (2×32240)+(9×7560)(2 \times 32240) + (9 \times 7560)
    Total received = 64480+6804064480 + 68040
    Total received = 132520 Ksh.
    The total amount of money she received is Ksh 132,520\boxed{\text{Ksh } 132,520}.

Part c(ii)

34.95%34.95\%

Determine correct to 4 significant figures the percentage profit the trader made from the sale of animals.

  1. Calculate the total cost of the animals.

    Total cost = 2c+9g=2(24800)+9(5400)=49600+48600=982002c + 9g = 2(24800) + 9(5400) = 49600 + 48600 = 98200 Ksh.
    (This matches the initial total cost given in the problem statement).

  2. Calculate the total profit.

    Total profit = Total received - Total cost
    Total profit = 132520−98200=34320132520 - 98200 = 34320 Ksh.

  3. Calculate the percentage profit.

    Percentage Profit=Total ProfitTotal Cost×100%\text{Percentage Profit} = \frac{\text{Total Profit}}{\text{Total Cost}} \times 100\% Percentage Profit=3432098200×100%\text{Percentage Profit} = \frac{34320}{98200} \times 100\% Percentage Profit≈0.349490835×100%\text{Percentage Profit} \approx 0.349490835 \times 100\% Percentage Profit≈34.9490835%\text{Percentage Profit} \approx 34.9490835\%
  4. Round the percentage profit to 4 significant figures.

    The first four significant figures are 3, 4, 9, 4. The fifth digit is 9, so we round up the fourth digit.
    Percentage Profit ≈34.95%\approx 34.95\%
    The percentage profit is 34.95%\boxed{34.95\%}.

Was this helpful?

Try one yourself

A new problem that tests the same skill.

Still stuck on this one?

Ask a follow-up, and the answer starts from this question.

Got a different question?Ask your own question
Handwritten step-by-step solution preview

Handwritten Step-by-Step Solution

Get this as a handwritten image on WhatsApp — like a tutor wrote it for you.

Try on WhatsApp