Govt Exams
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Topics in Quantitative Aptitude
The average of five consecutive even numbers is 24. What is the largest number?
Correct Answer:
B. 28
EXPLANATION
Let numbers be x, x+2, x+4, x+6, x+8. Sum = 5x + 20 = 120, so x = 20. Largest = 20 + 8 = 28.
If a number is divisible by both 9 and 11, it must be divisible by which of the following?
Correct Answer:
A. 99
EXPLANATION
Since 9 and 11 are coprime (HCF = 1), the number must be divisible by 9 × 11 = 99.
Q.393
Medium
How many ways can 5 books be arranged on a shelf?
Correct Answer:
B. 120
EXPLANATION
5!=120.
Q.394
Medium
Selling price Rs 840, profit 20%. Cost price?
Correct Answer:
B. Rs 700
EXPLANATION
CP=840×100/120=Rs 700.
Q.395
Medium
Pipe fills tank in 6 hrs, another empties in 12 hrs. Together?
Correct Answer:
B. 12 hours
EXPLANATION
Net=1/6-1/12=1/12. Time=12 hrs.
Q.396
Medium
Compound interest on Rs 10000 at 10% for 2 years?
Correct Answer:
B. Rs 2100
EXPLANATION
CI=10000×1.1²-10000=12100-10000=Rs 2100.
Q.397
Medium
Average of 5 numbers is 28. Excluding one, avg becomes 25. Excluded number?
Correct Answer:
A. 40
EXPLANATION
Sum=140. New sum=100. Excluded=40.
Q.398
Medium
Sum doubles in 8 years (SI). Rate of interest?
Correct Answer:
B. 12.5%
EXPLANATION
R=100/8=12.5%.
Q.399
Medium
A finishes work in 10 days, B in 15 days. Together?
Correct Answer:
B. 6 days
EXPLANATION
1/10+1/15=5/30=1/6. Together=6 days.
Find HCF of 144, 180, and 192.
Correct Answer:
A. 12
EXPLANATION
144 = 2⁴ × 3², 180 = 2² × 3² × 5, 192 = 2⁶ × 3.
Common factors: 2² and 3. HCF = 2² × 3 = 12.