Gilbert bought 3 shirts for $15.90 each, including tax. how much did he spend

So, as Gilbert bought 3 shirts -- we multiple $15.90 by 3 to get us, $47.70. However, as we need to include tax (20%) we find 20% of that cost. 10% of 47.70 is 4.77 -- we then double that as we are calculating 20%. That gives us 9.54 which we add onto the previous cost of the shirts: 47.70 + 9.54 = 57.24 (ANSWER)

On monday,mrs.wise bought 3 lbs of apples at $4per lb= 4*3=$12on tuesday ,20%off and she buy 5 lbs of apples = $4-20%=3.20*5lb=$16example: other wise when she buy 5lbs on monday she have to spend 4*5=20

All you have to do is multiply