You are Here: Home >< Maths

# HELP!!!!!!!!!!!!!! watch

1. Prospectors are drilling for oil. The cost of drilling to a depth of 50m is £500. To drill a further 50m costs £640 and hence the total cost of drilling to a depth of 100m is £1140. Each subsequent extra depth of 500m costs £140 more to drill than the previous 50m.
a) Show that the cost of drilling to a depth of 500m is £11300.
b) the total sum of money available for drilling is £76000. Find, to the nearest 50m, the greatest depth that can be drilled.
2. (Original post by Capsfree)
Prospectors are drilling for oil. The cost of drilling to a depth of 50m is £500. To drill a further 50m costs £640 and hence the total cost of drilling to a depth of 100m is £1140. Each subsequent extra depth of 500m costs £140 more to drill than the previous 50m.
a) Show that the cost of drilling to a depth of 500m is £11300.
b) the total sum of money available for drilling is £76000. Find, to the nearest 50m, the greatest depth that can be drilled.

What seems to be the problem so you ask for help with 12 exclamation marks ...
3. (Original post by TeeEm)
What seems to be the problem so you ask for help with 12 exclamation marks ...
I don't know where to start. I'm sooo confused
4. (Original post by Capsfree)
I don't know where to start. I'm sooo confused
ok what topic do you think is involved here?
5. (Original post by TeeEm)
ok what topic do you think is involved here?
Arithmetic series
6. Think about it. It goes up 140 quid every 50M extra. The first 50M = 500 quid, from 50-100 it is 640.. so from 100 to 150 it will be 780... 150 to 200 will be 920... continue that up to 450-500 which is 1760. Add all of the totals, you get 11300.
7. (Original post by Capsfree)
Arithmetic series
very good
they are saying

first 50 m .......total depth 50m ........... £500
next 50m ........total depth 100m ..........£(500 +140)
next 50m ........total depth 150m...........£(500 +140 x 2)
next 50m ........total depth 200m...........£(500 +140 x 3)

form an arithmetic progression by identifying the first term and common difference and use the standard formulas
8. (Original post by iMacJack)
Think about it. It goes up 140 quid every 50M extra. The first 50M = 500 quid, from 50-100 it is 640.. so from 100 to 150 it will be 780... 150 to 200 will be 920... continue that up to 450-500 which is 1760. Add all of the totals, you get 11300.
quid?
9. (Original post by iMacJack)
Think about it. It goes up 140 quid every 50M extra. The first 50M = 500 quid, from 50-100 it is 640.. so from 100 to 150 it will be 780... 150 to 200 will be 920... continue that up to 450-500 which is 1760. Add all of the totals, you get 11300.
Can you use the arithmetic series formula please?
10. (Original post by TeeEm)
very good
they are saying

first 50 m .......total depth 50m ........... £500
next 50m ........total depth 100m ..........£(500 +140)
next 50m ........total depth 150m...........£(500 +140 x 2)
next 50m ........total depth 200m...........£(500 +140 x 3)

form an arithmetic progression by identifying the first term and common difference and use the standard formulas
Thanks.
11. (Original post by Capsfree)
Thanks.
my pleasure

### Related university courses

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: October 19, 2015
Today on TSR

### Edexcel C2 Core Unofficial Markscheme!

Find out how you've done here

Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams