Question

find all pairs of consecutive odd natural number both of which are larger then 10 such that their sum is less then 40

Answer 1

heya

10< x + x+2 <40
10<2x+2<40
10<2x+2 and 2x+2<40
8<2x. and. 2x<38
4<x. and x<19

so x equal to 11,13,15,17

Answer 2

Answer:

(11, 13), (13, 15), (15, 17), (17,19)

Step-by-step explanation:

Let x be the smaller of the two consecutive odd natural number, so that the other one is x + 2.  Given x > 10 and x + (x + 2) < 40  ⇒ 2x < 38  ⇒ x < 19  ∴10 < x < 19  Since x is an odd number, x can take the values 11,13, 15 and 17.  ∴ Required possible pairs are (11, 13), (13, 15), (15, 17), (17,19).