Math, asked by akulrastogi2005, 9 months ago

a boy spends 10 on first day,20 on second day,40 on 3rd day. Find out how much he will spend in 12 days

Answers

Answered by vijayasarathi96

Answer:

10 +20+40+80+160+320+640+1280+2560+5120+10240+20480=40950

Answered by bap1299bhartisharma

Step-by-step explanation:

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QUESTION By default hide Solutions

A boy spends Rs.10 on first day, Rs.20 on second day, Rs.40 on third day and so on. Find how much, in all, will he spend in 12 days?

SOLUTION

Amount spent on 1st day = Rs. 10

Amount spent on 2st day = Rs. 20

Amount spent on 3st day = Rs. 40 and so on

Now,

2010=2,4020=2,

Thus, 10, 20, 40, ...... is a G.P. with first term, a = 10 and common ratio, r = 2 (r > 1)

∴ Total amount spent in 12 days = S¹²

Sn = a(rⁿ-1)

r-1

→ S¹²= 10(2¹²-1) = 10(2¹²-1)

2-1

→ 10(4096 - 1) = 10 x 4095 = 40950

Hence, the total amount spent in 12 days is Rs. 40950.

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