Question 828054: 1.A box contains 100 coins partly 5 rupee and 2 rupee,the total value of which is Rs.245.Find the numbers of both 2 & 5 rupee coins.
2.The sides of a triangle are in the ratio 2:3:4 and its perimeter is 36 cm.Find the greatest side of the traiangle in cm.
3.A man bought some milk and added 1 lit. water with every 6 lit. of milk and sold the mixture at the cost price of pure milk.Find his percentage of profit.
Answer by LinnW(1048)   (Show Source):
You can put this solution on YOUR website! Set t = number of 2 rupee coins
f = number of 5 rupee coins
The number of 2 rupee coins + the number of 5 rupee coins = 100
t + f = 100
(2 rupees)(no of two rupee coins) + (5 rupees)(no of 5 rupee coins) = 245 rupees
2t + 5f = 245
Solve the first equation for t
t + f = 100
subtract f from each side
t = 100 - f
substitute (100 - f) for t in 2t + 5f = 245
2(100 - f) + 5f = 245
200 -2f + 5f = 245
200 +3f = 245
subtract 200 from each side
3f = 45
f = 15
since t = 100 - f ,
t = 100 - 15 = 85
Check in 2t + 5f = 245
2(85) + 5(15) ?= 245
170 + 75 ?= 245
245 = 245, so the values check out.
2.The sides of a triangle are in the ratio 2:3:4 and its perimeter is 36 cm.Find the greatest side of the traiangle in cm.
Find the fraction of the perimeter for each side.
With side ratios of 2:3:4, add 2+3+4 = 9
The fractions of the perimeter are 2/9,3/9,4/9
The side lengths of the triangle with perimeter 36 are
(2/9)36 , (3/9)36, (4/9)36
72/9 , 108/9 , 144/9
8,12,16
3.A man bought some milk and added 1 lit. water with every 6 lit. of milk and sold the mixture at the cost price of pure milk.Find his percentage of profit.
The mixture will have a total of 7 liters.
The one liter added represents the profit.
Profit is 1/7 = 14.28%
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