Average - Study Mode

[#146] A cricketer whose bowling average is 12.4 runs per wicket takes 5 wickets for 26 runs and thereby decreased his average by 0.4. The number of wickets taken by him the last match was-
Correct Answer

(D) 85

Explanation

Solution: Let the number of wickets taken till the last match be x $$eqalign{
& Rightarrow frac{{12.4x + 26}}{{x + 5}} = 12 cr
& Rightarrow 12.4x + 26 = 12x + 60 cr
& Rightarrow 0.4x = 34 cr
& Rightarrow x = frac{{34}}{{0.4}} cr
& Rightarrow x = frac{{340}}{4} cr
& Rightarrow x = 85 cr} $$

[#147] The average of 11 players of a cricket team is decreased by 2 months when two of them aged 17 years and 20 years are replaced by two new players. The average age of the new players is-
Correct Answer

(B) 17 years 7 months

Explanation

Solution: Total age decreased = (11 × 2) months = 22 months = 1 year 10 months ∴ Average age of two new players $$left( {frac{{{ ext{35 years 2 months}}}}{2}}
ight)$$ = 17 years 7 months

[#148] The average monthly income of P and Q is Rs. 5050. The average monthly income of Q and R is Rs. 6250 and the average monthly income of P and R is Rs. 5200. The monthly income of P is-
Correct Answer

(B) Rs. 4000

Explanation

Solution: Let P, Q and R represent their respective monthly income Then, we have P + Q = (5050 × 2) = 10100.....(i) Q + R = (6250 × 2) = 12500.....(ii) P + R = (5200 × 2) = 10400.....(iii) Adding (i), (ii) and (iii), we get 2 (P + Q + R) = 33000 ⇒ P + Q + R = 16500 Subtracting (ii) from (iv), we get P = 4000 ∴ P's monthly income = Rs. 4000

[#149] The average of the ages of Sumit, Krishna and Rishabh is 43 and the average of the ages of Sumit, Rishabh and Rohit is 49. If Rohit is 54 years old, what is Krishna’s age?
Correct Answer

(B) 36 years

Explanation

Solution: Sumit + Krishna + Rishabh = 43 × 3 = 129.....(i) Sumit + Rishabh + Rohit = 49 × 3 = 147.....(ii) Subtracting (i) from (ii), we get: Rohit - Krishna = 18 ⇒ Krishna = 54 - 18 = 36

[#150] A library has an average of 510 visitors on Sundays and 240 on other days. What is the average number of visitors per day in the month of June beginning with a Sunday?
Correct Answer

(C) 285

Explanation

Solution: If a month beings with Sunday then there are 5 Sundays in that month. Total number of visitors comes on Sunday = 510 × 5 = 2550 Total number of visitors come on other days = 240 × 25 = 6000 ∴ Average number of visitor per day $$eqalign{
& = frac{{2550 + 6000}}{{30}} cr
& = frac{{8550}}{{30}} cr
& = 285 cr} $$