Question

EXERCISE 15 B 1. 17 less than four times a number is 11. Find the number. 2. If 10 be added to four times a certain number, the result is 5 less than five times a Find the number. 3. 2/3 of a number is 20 less than the original number. Find the original number. ​

Answer 1

Answer:

Q1) 7 Q2) 15

Step-by-step explanation:

Q1) 4x-17=11

4x=11+17

x=28÷4

x=7

Q2) 4x+10=5x-5

10+5= 5x-4x

15=x

Q3) ⅔x=x-20

Answer 2

Answer:

1. The number is 7.

2. The number is 15.

3. The number is 60.

Step-by-step explanation:

1. Let the number be x

 According to the question, 4x - 17 = 11

                                               4x = 11 + 17

                                               4x = 28

                                                 x = $\frac{28}{4}$

                                                 x = 7

The number is 7

2.  Let the number be 'a'

   According to the question, 10 + 4a = 5a - 5

                                                 10 + 5 = 5a - 4a

                                                  15 = a

  The number is 15

3. Let the number be x

 According to the question,  = $\frac{2}{3}$ x - 20

                                               2x = 3 (x - 20)

                                               2x = 3x - 60

                                               60 = 3x - 2x

                                               60 = x

 The number is 60.