A zoo visit costs R20 for adults and R10 for children. If R90 was spent on tickets, how many adults and children could have visited?

Let's break down the zoo challenge again, Elisa.

11 May 2026: Challenge - A visit to the zoo

The cost for an adult ticket is R20.
The cost for a child ticket is R10.
The total amount spent on tickets is R90.

Let $A$ be the number of adults and $C$ be the number of children.
The equation representing the total cost is:

$$20A + 10C = 90$$

• Step 1: Simplify the equation. Divide the entire equation by 10 to make it simpler:

  $$\frac{20A}{10} + \frac{10C}{10} = \frac{90}{10}$$ $$2A + C = 9$$

• Step 2: Find possible whole number combinations for adults ($A$) and children ($C$). We need to find values for $A$ and $C$ that are whole numbers (since you can't have a fraction of a person) and satisfy the equation $2A + C = 9$.

  • If $A = 1$: $2(1) + C = 9$ $2 + C = 9$ $C = 9 - 2$ $C = 7$ This means 1 adult and 7 children.

  • If $A = 2$: $2(2) + C = 9$ $4 + C = 9$ $C = 9 - 4$ $C = 5$ This means 2 adults and 5 children.

  • If $A = 3$: $2(3) + C = 9$ $6 + C = 9$ $C = 9 - 6$ $C = 3$ This means 3 adults and 3 children.

  • If $A = 4$: $2(4) + C = 9$ $8 + C = 9$ $C = 9 - 8$ $C = 1$ This means 4 adults and 1 child.

  • If $A = 5$: $2(5) + C = 9$ $10 + C = 9$ $C = 9 - 10$ $C = -1$ This is not possible, as the number of children cannot be negative.

• Step 3: Provide one answer for the first set of blanks. Let's use the combination of 1 adult and 7 children. How many are children? $\boxed{7}$ How many are adults? $\boxed{1}$

• Step 4: List other possible answers for the second set of blanks. Is there another answer? Yes. Here are the other valid combinations: Adults $\boxed{2}$ Children $\boxed{5}$ Adults $\boxed{3}$ Children $\boxed{3}$ Adults $\boxed{4}$ Children $\boxed{1}$