Word problem.

Question

A college student is traveling to santo domingo on spring break. He purchased 21 traveler's check worth $510, in denominations of $10, $40, or $50. He bought 4 times as many as $10 checks as $50 checks. How many checks in each denomination did he buy?

Answer 1

Let x = number of $10 checks

and y = number of $40 checks

and z = number of $50 checks

 

from what is given in the problem we can write down 3 equations :

 

x + y + z = 21

(4)z = x

10(x) + 40(y) + 50(z) = 510

 

solving these 3 equations , results in 

x = 12 ,  y = 6 and z = 3