geometric series: marty is training for a run....

[jaymath]

marty is training for a run. this week he ran for45 kms and intends to increase his distn by 10 % ech week. determine the total distance Marty will run after 10 weeks.

 

[tkhunny]

Have you considered building it?

45 + 45*1.1 + 45*1.1^2 + 45*1.1^3 + ... + 45*1.1^9

Add it up!

 

[jaymath]

Have you considered building it?

45 + 45*1.1 + 45*1.1^2 + 45*1.1^3 + ... + 45*1.1^9

Add it up!

can u pl tell me i ve t take 45 or 49.5 as my first i m stuck wr t start with n final ans pl. thnx.

 

[tkhunny]

I listed them ALL for you. Just add them up. Do you know how to do that?

45 + 45*1.1 + 45*1.1^2 + 45*1.1^3 + ... + 45*1.1^9

A little algebra

45(1 + 1.1 + 1.1^2 + 1.1^3 + ... + 1.1^9)

Inside the parentheses is a geometric series with initial value 1 and common ratio 1.1 and 10 terms.

 

[Deleted member 4993]

a + a*r + a*r² + a*r³.....a*r^n-2 + a*r^n-1 = a * (rⁿ - 1)/(r -1)

 

[jaymath]

THNX TO ALL OF U TO HELP SOLVING GEOMETRIC SERIES PROBLEM.