Question 281186
Let x = Number of 20c stamps
Therefore, 2x = Number of 32c stamps

20(x) + 32(2x) = 336
20x + 64x = 336
84x = 336
x = 4 (20c stamps)
x2 = 8 (32c stamps).

Verify:
4 x 20 = 80 cents
8 x 32 = 256 cents
80+256 = $3.36.