Ques 1.
Two mixtures A and B contain milk and water in the ratio 2:5 and 5:4 respectively. How many gallons of A must be mixed with 90 gallons of B so that the resultant mixture contains 40% milk.?
Solution :
(50+2x)/(40+5x) = 40/60
==> 150+6x = 80+10x
==> X = 70/7
A mixture = 2x+5x =7x = 70*7/4=122.5 gallons
Ques 2.
A bank offers 5% compound interest calculated on half-yearly basis. A customer deposits Rs. 1600 each on 1st January and 1st July of a year. At the end of the year, the amount he would have gained by way of interest is?
Solution :
1600*2.5%=40
1640*2.5%=41
1600*2.5%=40
Total Interest = 121
Ques 3.
Profit after selling a commodity for Rs524 is the same as loss after selling it for Rs.452. The cost price of the commodity is ?
Solution :
(524+452)/2=488
Ques 4.
In a mixture of milk and water 270 l, there is milk and water in ratio 7:5. How much water is added to get ratio 9:5 finally.
Solution :
270×7/12=157.5 milk
270-157.5=112.5 water
water to add = 157.5/112.5+x=9/5
==>x=25
Ques 5.
It is required to get 40% marks to pass an exam. A candidate scored 200 marks and failed by 8 marks. What were the maximum marks of that exam?
Solution :
208------40%
x --------100%
==>Maximum Marks = X= 520
Ques 6.
A trader has 60 kg of pulses, one part of which is sold at 8% profit and the rest is sold at 14% profit. He gains 12% on whole. What is the quantity sold at 14% profit?
Solution :
8 14
12
2. 4
From allegation we get ratio = 1:2
total 3 units from 1:2 , its equal to 60kgs
3units ------60
2units ----- X
14% profit quantity (X)= 40kgs
Ques 7.
By selling 144 hens Mahesh suffered a loss equal to the selling price of 6 hens. His loss % is ?
Solution :
144cp-144sp = 6sp
==> 144cp = 150sp
loss % = (6/150)*100=4%
Ques 8.
The price of an article is first increased by 20% and later on the price were decreased by 25% due to reduction in sales. Find the net percentage change in final price of Article.
Solution :
20-25-(20*25/100)=10%
Ques 9.
If A : B = 5 : 2 and B : C = 4 : 7, then C : A is ?
Solution :
A:B = 5:2
B:C = 4:7
Try to equal common digits in two ratios
A:B = 5:2 *2 = 10:4
A: B : C = 10:4:7
Ques 10.
kamal Chand sold a bike at a loss of 20%. Had he sold it for Rs. 3000 more he would have earned a profit of 10% instead of loss. Find the cost price of the bike.
Solution :
case-I :- cp=100x. sp= 80x. % of loss = 20%
case -II :- cp=100x sp=80x+3000 ; gain = 10%
==> ((80x+3000)-(100x))/100x)*100 =10
==>X=100
cp =100*3=10000
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