1. Sum of six consecutive numbers that are divisible by 3 is 99. Find the sum of the first two numbers.
2. 10% of ?% of 1000 = 150
A. 150
B. 1500
C. 300
D. 3000
3. The average of four consecutive odd integers is 24 less than the sum of these integers. Then which will be the largest of them?
4. The arithmetic mean of the five consecutive numbers a, a + 1, a+ 2, a + 3 and a + 4 is A, then the value of the median of these numbers is equal to:
A. 2
B. a + 3
C. a
D. a + 4
5. A man lent out Rs.9600 at [latex]\frac {9}{2}[/latex] % per annum for a year and 9 months. At the end of the duration, the amount he earned as S.I was:
A. 567
B. 756
C. 874
D. 784
Answers and Explanations
1. Answer - Option B
Explanation -
Difference between successive numbers divisible by 3 will be 3. Therefore, the series takes the form as below.
x - 6,x - 3, x, x + 3, x +6, x + 9
Sum of all terms in the series = 99 = x - 6 + x - 3 + x + x + 3 + x + 6 + x + 9 = 6x + 9
6x + 9 = 99
Or 6x = 90
Or x = 15
Sum of first two numbers = x - 6 + x - 3 = 2x - 9 = 2(15) - 9 = 21
2. Answer - Option A
Explanation -
Let the number to be found be N
Then, 10% of N% of 1000 = 150
Or [latex](\frac {10}{100})x(\frac {N}{100}) x 1000 = 150[/latex]
Or N = [latex]\frac {(150 x 100 x 100)}{(10 x 1000)} = 150[/latex]
3. Answer - Option A
Explanation -
Let the x, x + 2, x + 4 and x + 6 be the 4 consecutive odd integers.
We have to find the largest integer x + 6.
It is given that the average of these numbers is 24.
i,e., [latex]\frac {(x + x + 2 + x + 4 + x + 6)}{4} [/latex] = 24
4x + 12 = 24 x 4
4x = 84
x = [latex]\frac {84} {4} [/latex] = 21
Then x + 6 = 21 + 6 = 27
Hence, the answer is 27.
4. Answer - Option A
Explanation -
Let a, a + 1, a + 2, a + 3 and a + 4 be the given 5 consecutive numbers.
We have to find value of their median.
i.e, middle number of them = a + 2
It is given that, their average = arithmetic mean = A = [latex]\frac {(a + a + 1 + a + 2 + a + 3 + a + 4)}{5}[/latex]
A = [latex]\frac {(5a + 10)}{5} = \frac {5(a+2)}{5} = a + 2 [/latex]
a + 2 = A.
5. Answer - Option B
Explanation -
Given that, principal = P = Rs.9600, R = [latex]\frac {9}{2}[/latex] % and T = 1 year and 9 months = 1 + [latex]\frac {9}{12}[/latex] year = [latex]\frac {7}{4}[/latex] years.
Now, we have to find the S.I for [latex]\frac {7}{4}[/latex] years.
S.I = [latex]\frac {PRT}{100}[/latex] = Rs. [latex]9600 \times \frac {9}{2} \times \frac {7}{4} \times \frac {1}{100}[/latex] = 12 x 9 x 7 = 756
Hence, the required S.I amount is Rs.756