Pls friends answer the above question
Answers
Answer:
2,6,10,14 (or) 14,10,6,2
Step-by-step explanation:
Let the four consecutive numbers be (a - 3d), (a - d), (a + d), (a + 3d).
(i) Sum of four is 32:
⇒ a - 3d + a - d + a + d + a + 3d = 32
⇒ 4a = 32
⇒ a = 8.
(ii) Ratio of product of 1st and last term to extremes is 7:15
⇒ (a - 3d)(a + 3d)/(a - d)(a + d) = 7/15
⇒ 15(a - 3d)(a + 3d) = 7(a - d)(a + d)
⇒ 15a² - 135d² = 7a² - 7d²
⇒ 8a² = 128d²
⇒ 8(8)² = 128d²
⇒ 512 = 128d²
⇒ d² = 4
⇒ d = ±2
When a = 8, d = 2:
a - 3d = 2
a - d = 6
a + d = 10
a + 3d = 14
When a = 8, d = -2:
a - 3d = 14
a - d = 10
a + d = 6
a + 3d = 2
Therefore, the numbers are 2,6,10,14 (or) 14,10,6,2
Hope it helps!
HERE is your answer
Let the four consecutive terms of an A.P be a-3d, a-d, a+d and a+3d.
where = >>
extreme terms--> a-3d and a+3d.
mean terms--> a-d and a+d.
Note a trick: When we need to assume more than 2 consecutive terms then we take the consecutive terms in A.P in such a way that on sum the all (d)s eliminate.
eg:Three consecutive terms=
a ,a-d and a+d.
Now,
sum of four consecutive terms = 32
=>a-3d+a-d+ a+d+ a+3d = 32
=>4a = 32
=>a =8.
Now, according to the question-->
(a-3d)(a+3d)/(a-d)(a+d) = 7/15
=>a^2 - 9d^2/a^2 - d^2 = 7/15
{using identities(a-b)(a+b)= a^2 - b^2)
=>64- 9d^2/64 - d^2 = 7/15
now, by cross multiplication---->
=>15(64-9d^2) = 7(64- d^2)
=> 960 - 135 d^2 = 448 - 7 d^2
=>960 - 448 = -7d^2 + 135d^2
=>512 = 128d^2
=>d^2 = 4
=>d = plus minus 2
So,
when d = -2 and a = 8
the numbers are 14,12,10 and 8.
when d = 2 and a = 8
the numbers are 8,10,12 and 14.
thanks