Aptitude Discussion

Q. |
Average cost of 5 apples and 4 mangoes is Rs. 36. The average cost of 7 apples and 8 mangoes is Rs. 48. Find the total cost of 24 apples and 24 mangoes. |

✖ A. |
1044 |

✔ B. |
2088 |

✖ C. |
720 |

✖ D. |
324 |

**Solution:**

Option(**B**) is correct

Average cost of 5 apples and 4 mangoes = Rs. 36

Total cost = $36 \times 9 = 324$

Average cost of 7 apples and 8 mangoes = 48

Total cost = $48 \times 15 = 720$

Total cost of 12 apples and 12 mangoes = $324 + 720 = 1044$

Therefore, cost of 24 apples and 24 mangoes = $1044 \times 2$ = **2088**

**Edit:** For counter intutive cost outcome of this question, check discussion.

**PRATYUSH ANAND**

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*

Nothing is wrong, you actually got right answer. The apple cost is actually -24 in this question for these conditions to be possible.

Also 24 apples and 24 mangoes = 24*(-24) + 24*111 = 2088 which is correct :)

while solving cost problems with polynomials of more than first degree you should only consider the positive value from the roots you get while solving the polynomial

I don't know why answer doesn't come if we use equation in this question.

Let cost of each Apple be $A$

and Mango be $B$

then equation form:-

$5A+4B=36 \times 9$ ---(i)

$7A+8B=48 \times 15$ ----(ii)

$A=-24$ & $B=111$

Is it because here in question we should consider Apple and Mango as same entity,then only answer will come ????