   SEARCH HOME Math Central Quandaries & Queries  Question from Barbra, a student: here is two questions i need help with, 1.)A toastmasters tea was attended by 550 people. Students paid 75 cents for their tickets, and the adults paid $1.20. if the receipts totaled$525, how many adults and how many students attended? 2.) One cookie and six bars cost $2.00 at the girl guides bake sale. At the same sale, three bars and six cookies cost$2.10. Find the cost of one cookie and the cost of one bar. Hi Barbra,

I'll give you some help on the second problem and then you can finish it and try the first problem.

Suppose a cookie cost C dollars and a bar cost B dollars. The first sentence then tells you that

1 × C + 6 × B = 2.00.

The second sentence then becomes

6 × C + 3 × B = 2.10.

You can solve the first equation for the cost of a cookie and get

C = 2.00 - 6 × B

Substitute this value for C into the second equation and you are left with an equation in the single variable B. Solve this equation for B.

Penny     Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences.