# If two quantities x and y vary directly with each other, then ______ of their corresponding values remain constant.

**Solution:**

The table below shows the values of x and y and their ratio x/y.

x |
9 |
12 |
15 |
18 |
21 |

y |
3 |
4 |
5 |
6 |
7 |

x/y |
3 |
3 |
3 |
3 |
3 |

As evident from the above table as x is increasing y is also increasing. They are varying directly with each other. We can write,

x ∝ y

x = ky

x/y = k where k = proportionality constant = ratio of x and y

k = 3 in the given example

**✦ Try This: **What is the ratio of the values of x and y shown in the table below. Also establish what kind of relationship exists between x and y?

x |
12 |
13 |
14 |
15 |
16 |

y |
24 |
26 |
28 |
30 |
32 |

Ratio between x and y is

x/y = 12/24 = 13/26 = 14/28 = 15/30 = 16/32 = 1/2

Since k = 1/2 is a constant the relationship between the two variables is __direct one.__

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

**NCERT Exemplar Class 8 Maths Chapter 10 Problem 31**

## If two quantities x and y vary directly with each other, then ______ of their corresponding values remain constant.

**Summary:**

If two quantities x and y vary directly with each other, then the __ratio __of their corresponding values remain constant.

**☛ Related Questions:**

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