1. In what
ratio must water be mixed with milk costing Rs. 12 per litre to obtain a
mixture worth of Rs. 8 per litre?
Sol:
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12 -
8 : 8 - 0 = 1 : 2
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2. In what ratio
must rice at Rs. 9.30 per kg be mixed with rice at Rs. 10.80 per kg so that
the mixture be worth Rs. 10 per kg?
Sol:
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By
the rule of allegation (10.8 - 10) : (10 - 9.3) = 0.8 : 0.7 = 8 : 7
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3. A merchant
has 1000 kg of sugar, part of which he sells at 8% profit and the rest at 18%
profit. He gains 14% on the whole. The quantity sold at 18% profit is
Sol: ratio of first and second part = 4 : 6 = 2 : 3
Quantity of 2 kind = (1000*3/5) = 600 Kg
4.A sum of Rs. 4000
is lent out in two parts, one at 8% simple interest and the other at 10%
simple interest. If the annual interest is Rs. 352, the sum lent at 8% is
Sol: Total
interest of rs 4000 in 1 year = 52
Average rate = (352 * 100) / 4000 * 1 = 8.8%
by rule of allegation (8 - 8.8) : (10-8.8) = 1.2 : 0.8 = 3:2
part one = (4000*3/5) = 2400
5.729 ml of mixture
contains milk and water in the ratio 7 : 2. How much more water is to be
added to get a new mixture containing milk and water in the ratio 7 : 3
Sol: 729 *
7/9 = 567 ml, Water = 729 - 567 = 162
Let water added is x ml 567/(162 + x) = 7/3 or 1701 = 1134 + 7x or x = 81 ml
6.A sum of Rs. 312
was divided among 100 boys and girls in such a way that each boy gets Rs.
3.60 and each girl Rs. 2.40. The number of girls is
Sol: 312 -
240 : 360 - 312 = 3 : 2
Number of girl = 100*2/5 = 40
7.A jar full of
whisky contains 40% alcohol. A part of this whisky is replaced by another
containing 19% alcohol and now the percentage uf alcohol was found to be 26%.
The quantity of whisky replaced is
Sol: Ratio of
first and second = 7 : 14 = 1 : 2
Required quantity 2/3
8.A man covered a
distance of 2000 km in 18 hours partly by bus at72 kmph and partly by train
at 160 kmph. The distance covered by bus is
Sol: Average distance traveled = 1000/9
72 - 1000/9 : 160 - 1000/9 = 440/9 : 352/9 =5 : 4
distance traveled by bus = 18*5/9 = 10 distance traveled by bus in 10 hrs =
72 * 10 = 720
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