Maths help please!

Hi

I'm slightly stuck with this question and I'm struggling to see how to begin please can someone help?

Thanks in advance :smile:

Harold

Original post by science_geeks

@RDKGames

one is an arithmetic sequence (add 1000 each year)
one is a geometric sequence (multiply by 1.05 each year)

Can you write down those two position to term formulae?

Reply 4

science_geeks

Original post by mqb2766

one is an arithmetic sequence (add 1000 each year)
one is a geometric sequence (multiply by 1.05 each year)

Can you write down those two position to term formulae?

So, is the first one:

Un = a + (n-1)d so, 25,000 + (n-1)1000

Geometric sequence:

Un = ar^n-1 so, 22,000*1.05^n-1 ?? Why have you used 1.05 by the way?

Reply 5

Muttley79

Original post by science_geeks

So, is the first one:

Un = a + (n-1)d so, 25,000 + (n-1)1000

Geometric sequence:

Un = ar^n-1 so, 22,000*1.05^n-1 ?? Why have you used 1.05 by the way?

If something increase by 5% then you have 105/100 more the next year [100 + 5] which is 1.05

Reply 6

science_geeks

Original post by Muttley79

If something increase by 5% then you have 105/100 more the next year [100 + 5] which is 1.05

Okay, cool! Thank you :smile:

Reply 7

science_geeks

Original post by mqb2766

one is an arithmetic sequence (add 1000 each year)
one is a geometric sequence (multiply by 1.05 each year)

Can you write down those two position to term formulae?

I've got up to part d, but I'm unsure of what to do after this..

Reply 8

simon0

For part d, you want the total Lewis has earned to be greater than sum value T, so you want the total sum to be greater than T.

Your setup should be this: