# Both u and v vary directly with each other. When u is 10, v is 15, which of the following is not a possible pair of corresponding values of u and v

(a) 2 and 3

(b) 8 and 12

(c) 15 and 20

(d) 25 and 37.5

**Solution:**

As per the given problem statement:

u v

u/v = k

Where k is positive and called the proportionality constant

k = 10/15 = 2/3

From the alternatives given the values of u and v which give k = 2/3 are:

u = 2 and v = 3; u = 8 and v = 12; and 25 and 37.5

The only values of u and v which DO NOT form a pair corresponding to u = 10 and v = 15 are

u = 15 and v = 20

u/v = 3/4 ≠ k

**✦ Try This: **Both u and v vary directly with each other. When u is 24, v is 30, which of the following is a possible pair of corresponding values of u and v? (a) 39 and 52, (b) 25 and 30 (c) 12 and 15, (d) 24 and 28

As per the given problem statement:

u v

u/v = k

Where k is positive and called the proportionality constant

k = 24/30 = 4/5

From the alternatives given the values of u and v which give k = 4/5 is/are

u = 12 and v = 15

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

**NCERT Exemplar Class 8 Maths Chapter 10 Problem 1**

## Both u and v vary directly with each other. When u is 10, v is 15, which of the following is not a possible pair of corresponding values of u and v (a) 2 and 3, (b) 8 and 12, (c) 15 and 20, (d) 25 and 37.5

**Summary:**

Both u and v vary directly with each other. When u is 10, v is 15, of the given choices the one which is not a possible pair of corresponding values of u and v is u = 15 and v = 20.

**☛ Related Questions:**

- Both x and y vary inversely with each other. When x is 10, y is 6, which of the following is not a p . . . .
- Assuming land to be uniformly fertile, the area of land and the yield on it vary (a) directly with e . . . .
- The number of teeth and the age of a person vary (a) directly with each other, (b) inversely with ea . . . .

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