A contract is worth eighteen million six hundred forty-five thousand shillings. Lydia is to receive 25% of the contract value as her salary. The remaining amount is to be split equally between materia

The total contract amount is eighteen million six hundred forty-five thousand shillings.

Materials: $45\%$
Transport: $0.3 = 30\%$

Lydia should expect to earn $\boxed{\text{4,661,250 shillings}}$.

Task b) Help the bride to determine the new amount they have to pay for decoration.

An increase in payment of $3:2$ means the new payment is $\frac{3}{2}$ times the original payment.

The new amount the bride has to pay is $\boxed{\text{27,967,500 shillings}}$.

Task c) Help Lydia to determine the number of table clothes she will get from her rolls.

The lengths are $320 \text{ m}$, $480 \text{ m}$, and $520 \text{ m}$.

Prime factorization of each length:

The common prime factors are $2^3$ and 5.

So, each table cloth will be $40 \text{ m}$ long.

From the $320 \text{ m}$ roll: $\frac{320}{40} = 8$ table clothes
From the $480 \text{ m}$ roll: $\frac{480}{40} = 12$ table clothes
From the $520 \text{ m}$ roll: $\frac{520}{40} = 13$ table clothes

Lydia will get a total of $\boxed{\text{33 table clothes}}$.