Please help. Find the solution to (-1)/3 y.

If you roll two fair dice (one black die and one white die), in how many ways can you obtain a 4 on at least one die?

Money off coupons have been circulated to 300 households. only 2/5 of these were redeemed (used) in the local supermarket to get a free shampoo. what fraction of coupons were unused? (ps: write how you got the answer)

8litres of paint can cover 129.6 m². how much paint is required to paint an area of 243m²?