Since 4 peaches x 2 =8, you would would only be able to buy 6 mangos since $1.25 x 6 mangos =$7.5 so it would be $7.5+$8=$15.5 and 6 mangos+4 peaches=10 in total. And he would also save $5.00! :)
So what we're dealing with here is a similar triangle situation. Since ML is a midsegment, that means that IL and LJ are congruent. So, IL=LJ=13. This means that the whole side IJ is 26 (13+13=26). We also know that triangle IML and triangle IKJ are similar triangles, so their sides are proportional. This means that we can set up the ratio: 12/13 = x/26 and solve for x. After multiplying 26 to both sides of the equation, we find that x=24, so KJ=24.