Manhattan 5lb q no 25 page no 517

GRE Quant Problem Solving
1

Dwayne planted 70 acres with two types of beans: navy and pinto. Each acre of navy beans yielded 27 bushels and each acre of pinto beans yielded 36 bushels. If Dwayne grew twice as many bushels of pinto beans as navy beans, how many acres of pinto beans did he plant?

(A) 28
(B) 30
(C) 35
(D) 40
(E) 42

ans is 42

2

Let’s assume navy beans were planted in n acres and pinto beans were planted in p acres. So the amount of navy and pinto beans grown will be 27.n and 36.p bushels respectively (27 bushels per acre and n such acres).

So we have,

  • n + p = 70
  • 2.n.27 = p.36

Now it’s just an equation in 2 variables.

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