Undergrad How can John reduce his debt by paying into a joint account with Kelly?

[Buuuka86]

TL;DR

Joint account calculations

John owes Kelly £500.

John and Kelly have a joint account. Each of them pays £200 into the account every month, to spend on joint expenses.

If Kelly pays only half of her monthly contribution into the joint account (so £100), and John pays the usual (£200) how much will John's debt (£500) be reduced by?

Just trying to work out my finances ;)

 

[Mark44]

Summary:: Joint account calculations

John owes Kelly £500.

John and Kelly have a joint account. Each of them pays £200 into the account every month, to spend on joint expenses.

If Kelly pays only half of her monthly contribution into the joint account (so £100), and John pays the usual (£200) how much will John's debt (£500) be reduced by?

Just trying to work out my finances ;)

Is this a schoolwork question?

What have you tried to do to come up with an answer?

 

[Buuuka86]

It's a real life question :) I'm Kelly and my husband is John. I think the debt would be reduced by £50 every month but I'd love your help!

 

[mfb]

I agree.
You get the same result if you both pay $150 into the account and John gives you $50.