How did American factories change during World War II to support the war effort?

Ateacher has $80 to buy workbooks. each work book cost $3. if she buys as many workbooks as possible, how much money does she have leftover? a) $2 b) $4 c) $6 d) $8

5x−4≥12 or 12x+5≤−4 can you with this problem

The difference of two numbers is 40. find the numbers if 0.3 parts of one number is equal to 37.5% of the other one.