Answer:
He will have to cut off 1.25 inches.
Step-by-step explanation:
Take 5% of 5 inches
0.05(5)=0.25 inches
5 inches - 0.25 inches= 4.75 inches
4.75 inches is how wide the wood is after it shrinks.
Find how much he needs to cut off
4.75 inches - 3.5 inches=1.25 inches
He will need to cut off 1.25 inches in order for the block to fit exactly.