Ques 1.
Ravi goes downstream 120 km and upstream 40 km, taking 4 hrs each. What is the speed of current?
Down stream speed = 120/4 = 30 kmph
Up stream speed = 40/4 = 10 kmph
Speed current = (30-10)/2 = 10 kmph
Ques 2.
Three buses travel same distance with speeds in the ratio 3 : 4 : 5. What is the ratio of the times taken by them to cover the distance?
Solution :
Time ratio = 1/3 : 1/4 : 1/5
==> Ratio = 20 : 15 : 12
Ques 3.
Chocolates are bought at 54 for a rupee. How much must be sold for a rupee so as to gain 50%?
Solution :
= 54 * 100/150
= 36
Ques 4.
A bag contains 6 red and 4 blue balls. 2 balls are drawn one by one without replacement. What is the probability that the balls are alternately of different colors?
Solution :
When 1st is red = 6/10 * 4/9 = 12/45
When 1st is green = 4/10 * 6/9 = 12/45
When 1st is green = 4/10 * 6/9 = 12/45
Add two cases = 24/45 = 8/15
Ques 5.
Three pipes A, B and C can fill the tank in 10, 20 and 30 minutes respectively. If all the pipes are opened together and pipe B is turned off 5 minutes before the tank is fill. Then find the time in which the tank will full.
Solution :
Let total time taken by the pipes is T hrs, then
==> (1/10 + 1/20 + 1/30)*(T – 5) + (1/10 + 1/30)*5 = 1
==> (1/10 + 1/20 + 1/30)*(T – 5) + (1/10 + 1/30)*5 = 1
==> (11/60)*(T-5) +(4/30)*5 = 1
==> T = 75/11
Ques 6.
If the price of sugar is reduced by 10%. How many kilograms of sugar a person can buy with the same money which was earlier sufficient to buy 50 kg of sugar ?
Solution :
Let the original price = 100 Rs per kg
Then money required to buy 50 kg = 50*100 = Rs 5000
New price per kg is (100-90)% of Rs 100 = 90
So quantity of sugar bought in 5000 Rs is 5000/90 = 55.55 kg
Then money required to buy 50 kg = 50*100 = Rs 5000
New price per kg is (100-90)% of Rs 100 = 90
So quantity of sugar bought in 5000 Rs is 5000/90 = 55.55 kg
Ques 7.
A Company makes a profit of Rs.3,80,000, 10% of which is paid as taxes. If the rest is divided among the partners A, B and C in the ratio 5:3:4 then the share of A is
Solution :
10% = 380000*10/100 = 38000
Remaining = Rs.3,42,000
X = 3,42,000*3/12 = 85,500
Remaining = Rs.3,42,000
X = 3,42,000*3/12 = 85,500
Ques 8.
What half of a number is added to 468, it becomes five time of itself. What is the number ?
Solution :
x/2 + 468 = 5x
==>5x – x/2 = 468
==>9x/2 = 468
X = 468*2/9= 104
==>5x – x/2 = 468
==>9x/2 = 468
X = 468*2/9= 104
Ques 9.
Milk contains 40% water. What quantity of pure milk should be added to 150 liters of this milk to reduce the quantity of water to 30%?
Solution :
60 100
70
30 10
Ratio = 3 : 1
==> 150/X = 3/1
==> X = 50
Ques 10.
18 119 708 ? 14136 42405
18*7 -7 = 119
119*6 -6 = 708
708*5 -5 = 3535
