Five to the fourth power times four to the third power.
Let the number of blue marbles be x
number of yellow marbles = x/3
number of green = x- 90
ATQ
x + x/3 + x - 90 = 694
2x + x/3 = 784
(6x + x)/3 = 784
7x/3 = 784
x = 784 x 3/7
x = 112 x 3
x = 336
number of blue marbles = 336
1/80 = 0.0125
1/5 = 0.2
0.0125-0.2 = -0.1875
-0.1875 = -3/16