FINDING MISSING QUANTITIES IN DIRECT AND INVERSE PROPORTION

Find the missing variable:

Problem 1 :

y varies directly with x. If y = -4 when x = 2, find y when x = -6.

Solution

Problem 2 :

y varies inversely with x. If y = 40 when x = 16, find x when y = -5.

Solution

Problem 3 :

y varies inversely with x. If y = 7 when x = -4, find y when x = 5

Solution

Problem 4 :

y varies directly with x. If y = 15 when x = -18, find y when x = 1.6.

Solution

Problem 5 :

y varies directly with x. If y = 75 when x = 25, find x when y = 25.

Solution

Problem 6 :

If the cost of 9 toys is $333, find the cost of 16 such toys?

Solution

Problem 7 :

If 22.5 m of a uniform iron rod weight 85.5 kg, what will be the length of 22.8 kg of the same rod?

Solution

Problem 8 :

Complete the following table given that x varies inversely as y.

Solution

Problem 9 :

If 15 oranges cost $70, find the cost of 39 oranges.

Solution

Problem 10 :

A farmer has enough food to feed 20 animals in his cattle for 6 days. How long the food last if would there were 25 animals in his cattle?

Solution

Problem 11 :

Reema types 540 words during half an hour. How many words would she type in 6 minutes?

Solution

Problem 12 :

If 52 men can do a piece of work in 35 days, in how many men will do it in 14 days?

Solution

Problem 13 :

If 12 m of a uniform iron rod weights 42 kg. What will be the weight of 6 m of same rod?

Solution

Answer Key

1)  y = 12

2)  x = -128

3)  y = -5.6

4)  y = -1.33

5)  x = 8.33

6) Cost of 16 toys is $592.

7)  Length of the rod is 6 m.

8)  

9)   cost of 39 oranges is $182.

10)  4 days.

11)  Reema can type 108 words in 6 minutes.

12)  130 men will complete the work in 14 days.

13)   length of 6 m rod is 21 kg.