Question

a yard of fabric costs 7.85. lee plans to purchase 0.8 yards. if he gives the cashier $10, how much change should he receive?

Answer 1

$3.72 because 7.85 x .8 = 6.28 and 10 - 6.28 = 3.72

Answer 2

we said 
1yard = 7.85$ . so : 
0.8yards = x$ 
so x=(0.8*7.85)/1 = 6.28$
so if he gives th cashier 10$ he should receive : 10-6.28= 3.72$