If x varies inversely as y and y = 60 when x = 1.5. Find x, when y = 4.5.

Solution:

When x varies inversely as y then we can write:

x ∝ 1/y

x = k/y, where k is a +ve proportionality constant

xy = k

Given x = 1.5 and y = 60

xy = 1.5 × 60 = 90

If y = 4.5 then the new value of x will be

x × 4.5 = 90

x = 90/4.5

x = 20

✦ Try This: If x varies inversely as y and y = 240 when x = 6. Find x, when y = 144

When x varies inversely as y then we can write:

x ∝ 1/y

x = k/y

where k is a positive constant

xy = k

Given x = 6 and y = 240

xy = 6 × 240 = 1440

If y = 144 then the new value of x will be

x × 144 = 1440

x = 1440/144

x = 10

☛ Also Check: NCERT Solutions for Class 8 Maths Chapter 13

---

NCERT Exemplar Class 8 Maths Chapter 10 Problem 66

If x varies inversely as y and y = 60 when x = 1.5. Find x, when y = 4.5

Summary:

If x varies inversely as y and y = 60 when x = 1.5. X = 20, when y = 4.5

---

☛ Related Questions:

• In a camp, there is enough flour for 300 persons for 42 days. How long will the flour last if 20 mo . . . .
• A contractor undertook a contract to complete a part of a stadium in 9 months with a team of 560 per . . . .
• Sobi types 108 words in 6 minutes. How many words would she type in half an hour