Joanna bought only $0.15 stamps and $0.29 stamps. How many $0.15 stamps did she buy?
1) She bought $4.40 worth of stamps.
I rephrased this question to
15x + 29y = 440.
I understand how to get the solution of x=10, y=10. My question is how do I recognize that 15x+29y = 440 has 1 solution(x=10,y=10). When I first saw this problem I assumed that since I didn't have another equation in terms of x and y I couldn't solve for x and y since I didn't have 2 equations for 2 unknowns. I am just wondering if I see this on the GMAT then how I would recognize to go ahead with trying to find 1 solution.
Thanks.
1) She bought $4.40 worth of stamps.
I rephrased this question to
15x + 29y = 440.
I understand how to get the solution of x=10, y=10. My question is how do I recognize that 15x+29y = 440 has 1 solution(x=10,y=10). When I first saw this problem I assumed that since I didn't have another equation in terms of x and y I couldn't solve for x and y since I didn't have 2 equations for 2 unknowns. I am just wondering if I see this on the GMAT then how I would recognize to go ahead with trying to find 1 solution.
Thanks.
