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
Find sub-duplicate ratio of 9 : 16
Find the reciprocal ratio of `x/3 : y/7`
Find the ratio of the following in the simplest fcrm:
a4 + b4 and a3 - b3
Find the triplicate ratio of the following :
`2 sqrt 5 : 5 sqrt 2`
A cistern of milk caitains a mixture of milk and water in the ratio of 11 :4. If the cistern contains 60 litres of milk, how much more water must be added to make the
ratio of milk to water as 11:6 ?
A bag contains ₹ 1,600 in the form of ₹10 and ₹20 notes. If the ratio between the numbers of ₹10 and ₹20 notes is 2 : 3; find the total number of notes in all.
Find the mean proportional between 16 and 4
The ratio of zinc and copper in an alloy is 7 : 9. If the weight of copper in the alloy is 11.7 kg find the weight of zinc in it.
Neelam’s annual income is Rs. 288000. Her annual savings amount to Rs. 36000. The ratio of her savings to her expenditure is ______.
Find the ratio of the following:
