Aptitude Questions and Answers
If 9th of the month falls on the day preceding Sunday, then on what day will 1st of the month fall?
As per the question 9th of the Month=Saturday. (Day preceding Sunday)
Day name repeats after 7 days.
Therefore 9 minus 7=2nd of the given month is also Saturday.
Then 1st of the given month= Saturday Minus one day = Friday
The average of five numbers is 27. If one number is excluded, the average becomes 25. The excluded number is ?
(27*5)-(25*4)
135-100
35
A man can do a piece of work in 60 hours. If he takes his son with him and both work together then the work is finished in 40 hours. How many hours will the son take to do the same job, if he worked alone on the job?
If the man takes 60 hours to complete the work, then he will finish (1/60)thof the work in 1 hour.
Let us assume that his son takes x hours to finish the same work.
If they work together for 1 hour they will finish `1/60 + 1/x = 1/40` of the work.
Therefore,
x=120
The son, working alone would take 120 hours to complete the work.
I forgot the last digit of a 7 digit telephone number. If one randomly dial the final three digits after correctly dialling the four, then what is the chance of dialling the correct number?
It is given that last three digits are randomly dialled. Then each of the digit can be selected out of 10 digits in 10 ways.
Hence required probability
= `1/10 * 1/10 * 1/10`
= `1/1000`
Find the remainder when 6799 is divided by 7.
Remainder of `((67^99)/7)`==R==>`((63+4)^99)/7`
63 is divisible by 7 for any power, so required remainder will depend on the power of 4.
Require remainder:
`(4^99)/7==R==>(4^(96+3))/7`
`4^3/7==> 64/7==> (63+1)/7==R==>1`
On 5th December 1993, Nirmala and Raju celebrated their anniversary on Sunday. What will be the day of their anniversary in 1997 ?
Normal year jump +1 gain; Leap year jump +2 gain.
Years | Day Gain |
1994 | 1 |
1995 | 1 |
1996 (leap year) | 2 |
1997 | 1 |
Total days | 5 |
Sunday plus five days
- Monday
- Tue
- Wed
- Thursday
- Friday
A sum of money placed at compound interest doubles itself in 4 years. In how many years will it amount to 8 times?
Let,
Principal = Rs. 100.
Amount = Rs. 200.
Rate = r%
Time = 4 years.
Now,
`A = P*[1+ (r/100)]^n`;
`200 = 100*[1+(r/100)]^4`;
`2 = [1+(r/100)]^4`; ........... (i)
If sum become 8 times in the time n years,
then,
`8 = (1+(r/100))^n`;
`2^3 = (1+(r/100))^n`; ........(ii)
Using eqn (i) in (ii), we get;
`([1+(r/100)]^4)^3 = (1+(r/100))^n`;
`[1+(r/100)]^12 = (1+(r/100))^n`;
Thus, n = 12 years.
The average temperature for Wednesday, Thursday and Friday was 40oC. The average for Thursday, Friday and Saturday was 41oC. If temperature on Saturday was 42oC, what was the temperature on Wednesday?
Average temperature for Wednesday, Thursday and Friday = 40oC
Total temperature = 3*40 = 120oC
Average temperature for Thursday, Friday and Saturday = 41oC
Total temperature = 41*3 = 123oC
Temperature on Saturday = 42oC
Now,
(Thursday + Friday + Saturday) - (Wednesday + Thursday + Friday) = 123-120;
Saturday - Wednesday = 3
Wednesday = 42-3 = 39oC.
The difference between simple and compound interest for the fourth year is Rs. 7280 at 20% p.a. What is the principal sum?
Difference between CI and SI for nth year,
= `((Pr) /100) *[(1 +(r /100))^(n-1) -1]`
→ `7280 = ((P*20)/100) *[(1.2)^3-1]`
→ P = 50000.
Half percent, written as a decimal, is
As we know, 1% = 1/100
Hence, (1/2)% = (1/2 * 1/100) = 1/200 = 0.005