Question

Find the missing numbers on the double number line.

• A. 30 and 20
• B. 25 and 40
• C. 25 and 30
• D. 10 and 25

Answer 1

The correct option is C 25 and 30

(a)



As the double number lines represent an equivalent ratio, so ratio at the first marking = ratio at the second marking.

5:10 = 10:20

$\frac{5}{10}=\frac{10}{20}$

Now, the ratio at the third marking is $\frac{5}{10}=\frac{15}{y}$.

Solve for y

In the first number line, when the antecedent 5 is multiplied by 3, we get 15. Hence, we should multiply the consequent 10 by 3 in the second number line to get 30.



Therefore, the missing number in the ratio at the third marking is 30.

Now, the ratio at the fifth marking is$\frac{5}{10}=\frac{x}{50}$

Solve for x

In the second number line, when the consequent 10 is multiplied by 5 we get 50. Hence, we should multiply the antecedent 5 by 5 in the first number line to get 25.


Hence, the missing number in the ratio at the fifth marking is 25.