The sum of four consecutive numbers in an AP is 32 and the ratio of the product of the
first and the last terms to the product of the two middle terms in 7:15. Find the numbers.
Answers
Answer:
Four consecutive numbers are 2, 6, 10 and 14
Step-by-step explanation:
Lets consider four consecutive numbers in AP be (a - 3d), (a - d), (a + d) and (a + 3d)
So, according to the given data the sum of four consecutive numbers is 32
a-3d + a - d + a + d + a + 3d = 32
4a = 32
a = 32/4
a = 8 ......(1)
Now, ratio of the product of the first and the last terms to the product of the two middle terms in 7:15 i,e
(a - 3d)(a + 3d)/(a - d)(a + d) = 7/15
15(a² - 9d²) = 7(a² - d²)
15a² - 135d² = 7a² - 7d²
15a² - 7a² = 135d² - 7d²
8a² = 128d²
Putting the value of a = 8 in above we get.
8(8)² = 128d²
128d² = 512
d² = 512/128
d² = 4
d = 2
So, the required four consecutive numbers are
8 - (3*2)
8 - 6 = 2
8 - 2 = 6
8 + 2 = 10
8 + (3*2)
8 + 6 = 14
Four consecutive numbers are 2, 6, 10 and 14