Advertisements
Advertisements
प्रश्न
The 4th term of a G.P. is 16 and the 7th term is 128. Find the first term and common ratio of the series
Advertisements
उत्तर
The 4th term of a G.P. = 16
`=> ar^(4-1) = 16`
7th term of G.P. = 128
`=> ar^(7-1) = 128`
so, `(ar^3)/(ar^6) = 16/128`
`=> 1/r^3 = 1/8`
=> r = 2
`ar^3 = 16`
`a xx 2^3 = 16`
a x 8 = 16
a = 2
APPEARS IN
संबंधित प्रश्न
Convert the following percentage to fractions and ratio:
0.25%
If a : b = 4 : 7, find the following:
`(6"a" - "b")/("a" + 3"b")`
Two numbers are in the ratio 5 : 7 and the difference of their squares is 600. Find the numbers.
What quantity must be subtracted from each term of the ratio 39 : 89 to make it equal to 2 : 5 ?
In winter, a school opens at 10 a.m. and closes at 3.30 p.m. If the lunch interval is of 30 minutes, find the ratio of lunch interval to total lime of the class periods.
Which of the following numbers are in continued proportion:
6, 12 and 24
If `(2"y"+5"x")/(3"y"-5"x")=2 1/2`, find x, if y = 70
Find the compounded ratio of: (a – b) : (a + b), (a + b)2 : (a2 + b2) and (a4 – b4) : (a2 – b2)2
Find the sub-duplicate ratio of `(1)/(4) : (1)/(9)`
A metal pipe 3 metre long was found to weigh 7.6 kg. What would be the weight of the same kind of 7.8 m long pipe?
