Ques 1.
5, 14 , 40 , 117 , ?
Solution :
5*3-1 = 14
14*3-2 = 40
40*3-3 = 117
117*3-4 = 347
Ques 2.
I. X2 = 1849 II. Y = (1849)^1/2
Solution :
X = ±43
Y = 43
x≤y
Y = 43
x≤y
Ques 3.
P takes twice as much time as Q and thrice as much time as R to finish a piece of work. Working together they can finish the work in 6 days. R can do the work alone in ?
Solution :
1/x+2/x+3/x = 1/6
6/x = 1/6
x = 36
R = 3/x = 3/36 = 1/12 = 12 days
6/x = 1/6
x = 36
R = 3/x = 3/36 = 1/12 = 12 days
Ques 4.
1006.7+12328.98-5644.64 = 12543+ ?
Solution :
13335.68-5644.64 = 12543 + ?
7691.04 = 12543 + ?
? = 4851.96
7691.04 = 12543 + ?
? = 4851.96
Ques 5.
A certain sum of money amounts to Rs.800 in 2 years and to Rs. 920 in 3 years then the is
Solution :
==>(A2 – A1)/ T2-T1
==>(920-800) /1 = 120
==>P = 800-240 = 560
==>(920-800) /1 = 120
==>P = 800-240 = 560
Ques 6.
Four years ago, the ratio of the ages of P and Q was 5 : 9. 8 years hence the ratio will be 2 : 3 respectively. Find the present age of Q?
Solution :
4years ago P:Q ration = 5:9 (Difference = 4)
8 years hence P:Q ratio = 2:3 ( Difference =1)
new ratios :
4 years ago = 5:9 *1 = 5:9
8 years hence = 2:3 *4 = 8:12
Difference in Q ratio = 12-9 = 3 units
3 units ----------- 12 years
12 units --------- ?
Q age 8 years hence = 48 years
Present age of Q = 48-8 = 40 years
Ques 7.
The average age of P and Q 10 years ago was 20. The average age of P, Q and R today is 30, so what will be the age of R after 5 years.
Solution :
P+Q = 60.
P,R,Q = 90
so Age of Q = 30+5 = 35
P,R,Q = 90
so Age of Q = 30+5 = 35
Ques 8.
The length and breadth of a rectangle are increased by 30% and 20% respectively. Its area will be increased by
Solution :
30 + 20 + (30*20/100) = 56%
Ques 9.
Milk contains 20% water. What quantity of pure milk should be added to 50 liters of milk to reduce the quantity of water to 12% ?
Solution :
Pure Milk in 50 liters milk = 80*50/100 = 40
Water in 50 liters milk = 20*50/100 = 10
==> (40+x) / 10 = 88/12 = 22/3
==>3*( 40+x) = 220
==> 120+3x =220
==> X = 100/3 = 33.33
==> X = 100/3 = 33.33
Ques 10.
P,Q and R shared the profit in a business in the ratio 5:7:8 and partnered for 14 months, 8 months and 7 months. Ratio of their investments is
Solution :
Rs. x for 14 months, Rs. y for 8 months and Rs. z for 7 months
==> 14x : 8y : 7z = 5 : 7 : 8
==> 14x/8y = 5/7
==> y = (49/20)x
==> 14x : 8y : 7z = 5 : 7 : 8
==> 14x/8y = 5/7
==> y = (49/20)x
14x/7z = 5/8
==>z = (16/5)x
==>z = (16/5)x
x:y:z = x:(49/20)x:(16/5)x
20:49:64