Question

Lisa had 1750 stamps. Mark had 480 fewer stamps than Lisa. Lisa gave some stamps to Mark. Now Mark has three times as many stamps as Lisa. How many stamps did Mark have at first? How many stamps does Lisa have now? Explain.

Answer 1

Given that Lisa had 1,750 stamps and Mark had 480 fewer stamps than Lisa.

Thus, the number of stamps Mark had is 1,750 - 480 = 1,270

Given that Lisa gave some stamps to Mark which makes Mark to have three times as many stamps as Lisa.

Let the number of stamps that Lisa gave to Mark be x, then

$3(1,750 - x) = 1,270 + x \\ \\ \Rightarrow5,250-3x=1,270+x \\ \\ \Rightarrow x+3x=5,250-1,270 \\ \\ \Rightarrow 4x=3,980 \\ \\ \Rightarrow x= \frac{3.980}{4} =995$

Thus, Lisa gave Mark 995 stamps.

Therefore, the number of stamps that Lisa have now is 1,750 - 995 = 755.