The ratio of red blocks to green blocks in a set is 3:4. The set contains 56 green blocks. How many blocks are red?
r/g = 3/4 = r/56
3* 56 / 4 = r
r = 3*14 = 42
or
number of reds : green = 3:4 = 3x : 4x
but 4x = 56
x = 14
reds = 3x = 42
greens = 4x = 56
so total = 7x = 7(14) = 98