10th CBSE math solution for exercise 5.2 part 9

This page 10th CBSE math solution for exercise 5.2 part 9 is going to provide you solution for every problems that you find in the exercise no 5.2 part 9

10th CBSE math solution for exercise 5.2 part 9

(19) Subba Rao started work in 1995 at an annual salary of Rs 5000 and received and increment of 200 each year. In which year did his income reach Rs.7000

Solution:

5000,5200,,...........7000

a = 5000    d = 5200 - 5000      a n = 7000 

                     = 200

 a n = a + (n - 1) d

 7000 = 5000 + (n - 1) 200

 7000 - 5000 = (n - 1) 200 

   2000 = (n - 1) 200

  n - 1 = 2000/200

  n - 1 = 10

   n = 10 + 1

   n = 11

Therefore,11th year his salary will be 7000.


(20) Ramkali saved Rs.5 in the first week of a year and then increased her weekly savings by Rs 1.75. If the nth week,her weekly savings become Rs.20.75,find n.

Solution:

a = 5  d = 1.75  an = 20.75

 a n = a + (n - 1) d

 20.75 = 5 + (n - 1) 1.75

 20.75 - 5 = (n - 1) 1.75

  15.75 = ( n - 1) 1.75

  15.75/1.75 = n - 1

   9 = n - 1

   n - 1 = 9

    n = 9 + 1

    n = 10




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