Easy #10

Algebra Level 2

While shopping this week I misread my shopping list and bought 5 5 loaves of bread and 2 2 bottles of milk. So I went back to the supermarket, got a full refund, and bought 2 2 loaves of bread and 5 5 bottles of milk. This cost me $ 4.20 \$4.20 less than my first purchase. Between bread and milk, which cost more and by how much?

Milk, $ 1.40 \$1.40 Bread, $ 1.40 \$1.40 Milk, $ 4.10 \$4.10 Bread, $ 4.10 \$4.10

Victor Loh by Victor Loh , 19, Singapore

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

1 solution

Tom Dufall
Jul 27, 2014

Let B = Bread, M = Milk, and the cost of the cheapest trip is x. My first shopping trip cost $4.20 more than the cheapest trip, 5 B + 2 M = x + 4.2 5B + 2M = x + 4.2 My second trip 2 B + 5 M = x 2B + 5M = x Now I subtract the equation for the 2nd trip from the 1st trip and get: 3 B − 3 M = 4.2 3B - 3M = 4.2 Rearrange it to compare the prices 3 B = 3 M + 4.2 3B = 3M + 4.2 We want to compare 1:1, not 3:3, so divide by 3 B = M + 1.4 B = M + 1.4 So the price of bread is $1.40 more than the price of milk.

1 Helpful 0 Interesting 0 Brilliant 0 Confused

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...