iamseer wrote:

A farmer has an apple orchard consisting of Fuji and Gala apple trees. Due to high winds this year 10% of his trees cross pollinated. The number of his trees that are pure Fuji plus the cross-pollinated ones totals 187, while 3/4 of all his trees are pure Fuji. How many of his trees are pure Gala?

A. 22

B. 33

C. 55

D. 77

E. 88

We can solve using 2x2 Matrix fairly quickly:

_________gala__not gala___total

fuji______0.1x___0.15x____0.25x

not fuji __0.75x___0_______0.75x

total_____187____0.15x______x

187 = 0.85x = 85/100x = 17/20

11*17 = 17/20x

>> x = 220 >> 0.15x = 33