In a G.P., the 3rd 3^{\text {rd }} term is 24 and the 6th 6^{\text {th }} term is 192 .Find the 10th 10^{\text {th }} term.

Answer: The 10th10^{\text{th}} term is 3072.

Step-by-step solution

Step 1: Define the general term of a G.P.

The general term of a Geometric Progression (G.P.) is given by the formula an=arn−1a_n = ar^{n-1}, where ana_n is the nthn^{\text{th}} term, aa is the first term, and rr is the common ratio.

Step 2: Formulate equations from given terms

We are given that the 3rd3^{\text{rd}} term is 24 and the 6th6^{\text{th}} term is 192. Using the general term formula, we can write these as two equations: ar2=24ar^2 = 24 and ar5=192ar^5 = 192.

Step 3: Find the common ratio (r)

To find the common ratio rr, we can divide the equation for the 6th6^{\text{th}} term by the equation for the 3rd3^{\text{rd}} term. This simplifies to r3=8r^3 = 8, which means r=2r = 2.

Step 4: Find the first term (a)

Now that we have the common ratio r=2r=2, we can substitute it back into the equation for the 3rd3^{\text{rd}} term (ar2=24ar^2 = 24) to find the first term aa. This gives us a(2)2=24a(2)^2 = 24, which simplifies to 4a=244a = 24, so a=6a = 6.

Step 5: Calculate the 10th term

Finally, we need to find the 10th10^{\text{th}} term. Using the general formula an=arn−1a_n = ar^{n-1} with a=6a=6, r=2r=2, and n=10n=10, we get a10=6(2)9a_{10} = 6(2)^9. Calculating 29=5122^9 = 512, we find a10=6×512=3072a_{10} = 6 \times 512 = 3072.

More from this chapter

All Sequences and Series solutions →

Solve your own maths question free →