Let the number of bags to be purchased be x
Option Val : 250 + 1.50x
Option Sally : 100 + 4x
For Val to be the cheaper option:
250 + 1.5x < 100 + 4x
100 + 4x > 250 + 1.5x
100 + 4x - 100 > 250 + 1.5x - 100
4x > 150 + 1.5x
4x - 1.5x > 150 + 1.5x - 1.5x
2.5x > 150
x > 150 ÷ 2.5
x > 60
To make Val the cheaper option, he needs to buy more than 60 bags of lettuces.
If she is setting up a proportion to find the percent, the value of m would be any variable and the value of n would be 100. When she solves the problem, m=65%.
13/20 is part out of whole. The rest of the proportion will be "percent out of 100"; since we don't initially know the percent, we use a variable. Thus we have
13/20 = m/100
Cross multiply:
20*x = 13*100
20x = 1300
Divide both sides by 20:
20x/20 = 1300/20
x = 65
Four is the answer I believe because if you go through it seems to be four