Wayne goes to a fruits vendor to purchase mangoes and oranges. The cost of 4 mangoes is $10, and the cost of 5 oranges is $10. If Wayne buys fruits worth $31, he has purchased at least how many mangoes?
Pick one:
A) 1
B) 2
C) 6
D) 8
E) 13
Cost of each mango = $10 / 4 = $2.50.   Cost of each orange = $10 / 5= 
<gadget id="calculator">10 / 5</gadget>
<output>2</output>
$2.   Let number of mangoes be m, and number of oranges be o.   Then 2.5m + 2o= 31   =&gt; 5m + 4o = 62   =&gt; 5m = 62 - 4o   To find minimum m, we need to maximize o, and ensure that (62 - 4o) is divisible by 5.   o = 3, m = (62 - (4)3) / 5 = 10.   o = 8, m = (62 - (4)8) / 5 = 6.   o = 13, m = (62 - (4)13) / 5 = 2.   More than this, m will go -ve. So, Wayne has to purchase at least 2 mangoes.   Answer: 2
<result>B</result>
Wayne goes to a fruits vendor to purchase mangoes and oranges. The cost of 4 mangoes is $10, and the cost of 5 oranges is $10. If Wayne buys fruits worth $31, he has purchased at least how many mangoes?