1. Ajit has a certain average for 9 innings. In the tenth innings, he scores 100 runs thereby increasing his average by 8 runs. His new average is:
अजीत के पास 9 पारियों के लिए एक निश्चित औसत है। दसवीं पारी में, उसने 100 रन बनाए जिससे उसका औसत 8 रन बढ़ गया। उनका नया औसत है:
A.20
B.21
C.28
D.32
Answer: C. 28
Solution: Let Ajit’s average be x for 9 innings
So, Ajit scored 9x run in 9 innings.
In the 10th inning, he scored 100 runs then average became (x+8). And he scored (x + 8) × 10 runs in 10 innings.
Now,
⇒9x+100=10×(x+8) or ,9x+100
=10x+80 or,
x=100−80
or,
x=20
New average=(x+8)
=28runs
2. The average temperature for Wednesday, Thursday and Friday was 40°C. The average for Thursday, Friday and Saturday was 41° C. If temperature on Saturday was 42° C, what was the temperature on Wednesday?
बुधवार, गुरुवार और शुक्रवार का औसत तापमान 40°C था। गुरुवार, शुक्रवार और शनिवार का औसत तापमान 41°C था। यदि शनिवार को तापमान 42°C था, तो बुधवार को तापमान क्या था?
A. 39° C
B. 44° C
C. 38° C
D. 41° C
Answer: A. 39° C
Solution: Average temperature for Wednesday, Thursday and Friday = 40° C
Total temperature = 3 × 40 = 120° C
Average temperature for Thursday, Friday and Saturday = 41° C
Total temperature = 41 × 3 = 123° C
Temperature on Saturday = 42° C
Now,
(Thursday + Friday + Saturday) – (Wednesday + Thursday + Friday) = 123 – 120;
Saturday – Wednesday = 3
Wednesday = 42 – 3 = 39° C
3. The average of the first five multiples of 9 is:
9 के प्रथम पाँच गुणजों का औसत है:
A. 20
B. 27
C. 28
D. 30
Answer: B. 27
Solution: Required average=total sum of multiple of 9/5
=9+18+27+36+45/5=27
Note that, average of 9 and 45 is also 27.
And average of 18 and 36 is also 27.