Direct and Inverse Proportions Test - 1

Explanation:

This is a question of inverse proportion as with increase in people the days food will last will decrease

So, in inverse proportion the constant is taken as x X y

40 X 10=(40+10) X a( where a= the days food will last)

400=50 a

400/50= a

8 days= a

Explanation:

Money earned for 12 days= Rs 1440

So , money earned in 1 day= 1440/ 12=

Rs 120

So , money earned in 30 days= 120 X30= Rs 3600

Explanation:

Cost of 18 pens=  Rs 234

So Cost of 1 pen= 234/18=13

So a dozen pens( 12 pens ) will cost=

12 X13= Rs 156

Explanation:

As x and y varies inversely then, x=k/y,where k is any constant , so k=x X y. So the answer is x X y

Explanation:

8:12::6:a

→8/12=6/a

→8a=6X12

→a=6X12/8

→a=72/8

→a=9

So the answer is 9

Explanation:

This is a question of inverse proportion as with decrease in speed the time taken will increase.

In inverse proportion the constant is given by x X y

So, 54 X 2.5= 45 X a( where  a is the time taken)

135/45= a

3 hours=a

Explanation:

This is a question of inverse proportion as with decrease in number of labourers the time taken to complete the work will increase.

So , in inverse proportion the constant is given by x X y

So, 25 X 4= 20 X a( where a is the time taken to build the wall)

100= 20 a

100/20= a

5 days = a

Explanation:

As x and y varies directly that is x=ky where ,k is a constant, then k= x/y.So the correct answer is x/y

Explanation:

16 X 9=12 X m

16 X 9/12 = m

144/12= m

12=m .So the answer is 12

Explanation:

This is a question of direct proportion as with increase in height of tree the height of shadow increases

So,  in direct proportion the constant value is taken as X/ Y

20/8=h/10( where h is the height of the tree)

8h=20X 10

h=200/8=25m