Exercises - XXV , XXVI& XXVII

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Exercise-XXV, XXVI & XXVII

Exercises - XXV , XXVI& XXVII

Exercise-XXVI »

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Exercise-XXV

The value of a coin varies directly to the square of its radius when its thickness is constant. The radius of a coin is 1.5'' and its value is $ 2. What will be the radius of a coin if its value is $ 5

Sol:

The age of Ramson is 4 times that of his son. 5 years ago Ramson was nine times as old as his son at that time. The present age of Ramson is

Sol:	Let the Ramson age be 4x yrs
	Ramson's son age be x yrs
	4x – 5	=	9(x – 5)
	4x – 5	=	9x – 45
	40	=	5x
	x	=	8
	Ramson's present age	=	4x yrs
		=	4 × 8
		=	32

In an orchard

of the trees are mango trees. If the total number of trees is 840, Find the number of other trees in the orchard

Sol:	Number of trees	=	840
	Number of mango trees	=
		=	140
	Number of other trees	=	840 – 140
		=	700

A fruit seller buys oranges at 5 for $ 8 and sold at 2 for $ 5. Find the profit %

Sol:	Cost price of each orange	=
		=	$ 1.60
	Selling price of each orange	=
		=	$ 2.50
	Profit	=	$ 2.50 – $ 1.60
		=	$ 0.90

Find the cost price of an article which is sold for $220 at a loss of 12%

Sol:	If CP is $ 100 then SP will be $ 100 – $ 12 = $ 88
	If CP is $ 100 SP will be $ 88
	If SP is $ 220 then the CP will be
		=	$ 250

A Levis store gave a discount of 15% on all garments purchased. What will a customer pay for a phant costing $ 720

Sol:	Discount	=	15 %
	Price of the phant	=	$ 720
	Discount	=
		=	$ 108
	Price after discount	=	$ 720 – $ 108
		=	$ 612

By selling 18 chocolates a trader loses the selling price of 2 chocolates. Find his loss %

Sol:	Let SP of 1 chocolate	=	$ 1
	SP of 18 chocolates	=	$ 18
	Loss	=	$ 2
	Cost price	=	Selling price + loss
		=	$ 18 + $ 2
		=	$ 20

A car takes half of the time taken by a truck to go from P to Q. A truck takes 20 hrs to go for the same journey. What is the speed of the truck if the speed of the car is 120 mph

Sol:	Time taken by car	=
		=	10 hrs
	Distance covered by car	=	120 × 10
		=	1200 miles
	Distance covered by truck	=	1200 miles
	Time taken by the truck	=	20 hrs
	Speed of the truck	=
		=	60 mph

'A' goes 10 miles distance with average speed of 6 mph while rest 20 miles he travels with an average speed of 15 mph. What is the average speed of A ?