Answer:
25 cent stamps = 13 and 29 cent stamps = 15
Step-by-step explanation:
x = 25 cent stamps and y = 29 cent stamps
x + y = 28......x = 28 - y
0.25x + 0.29y = 7.60
0.25(28 - y) + 0.29y = 7.60
7 - 0.25y + 0.29y = 7.60
-0.25y + 0.29y = 7.60 - 7
0.04y = 0.60
y = 0.60 / 0.04
y = 15 <===== 29 cent stamps
x + y = 28
x + 15 = 28
x = 28 - 15
x = 13 <===== 25 cent stamps
lets check it...
0.25x + 0.29y = 7.60
0.25(13) + 0.29(15) = 7.60
3.25 + 4.35 = 7.60
7.60 = 7.60 (correct..it checks out)
