Aptitude Discussion

Q. |
The average score of a cricketer for ten matches is 38.9 runs. If the average for the first six matches is 42, then find the average for the last four matches. |

✖ A. |
33.25 |

✖ B. |
33.5 |

✔ C. |
34.25 |

✖ D. |
35 |

**Solution:**

Option(**C**) is correct

Total sum of last 4 matches

$= (10 \times 38.9) – (6 \times 42)$

$= 389 – 252 = 137$

Average

\(=\dfrac{137}{4}\)

\(=34.25\)

**Edit:** For an alternate solution, check comment by **Chirag Goyal.**

**Ali Jan**

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sorry, If you solve above finally you will get x=34.25 instead of 34.22.

**Chirag Goyal**

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Alternate Solution

$\text{Avg. of Last four Innings}$ $= 38.9 - \left(\dfrac{42-38.9}{4}\right)\times6 = 34.25$

**Avijit**

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wrong ans......

**Vivek Joshi**

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I experienced (also saw in comments later)

Please change the answer..

Thnx.

**Sibaram Behera**

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hi,the correct ans ic 'C' but it indicate wrong ans means 'D'.............PLEASE CHANGE THE OPTIONS

**Ridhima**

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the solution is correct but the option chosen is C not D.

**Ridhima**

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hey , the answer is correct but you have picked the wrong option.

If there are (p+q) elements in a set but the average of p elements is 'r' and the average of q elements is 's' then the average of all the elements of the set is given by $$\frac{pr+qs}{p+q}$$

so here, p=6, q=4, r=42, s= x(unknown ) , average of all elements = 38.9

by substituting values in above formula we get

$$\frac {42*6+x*4}{6+4}=38.9$$

$$x=34.22$$