So friends go to the cinema and buy 1 large tub of popcorn, 4 fizzy drinks and 10 packets of crisps. The bill comes to £10.89
Some other friends go to the cinema and buy 1 large tub of popcorn, 3 fizzy drinks and 7 packets of crisps. The bill comes to £8.64
How much is 1 large tub of popcorn, 1 fizzy drink and 1 packet of crisps?
I got:
1P + 4D + 10C = 10.89
1P + 3D + 7D = 8.64
When I subtract one from the other I get: 1D + 3C = £2.25
How do I get the prices for 1 large tub of popcorn, 1 fizzy drink and 1 packet of crisps from there??
Many thanks for any help.
It would be a good idea to state "P is the cost of 1 large tub of popcorn, D is the cost of one fizzy drink, and C is the cost of one packet of crisps". Also, you mean "7C", not "7D". Other than that, yes, those are the two equations.
From D+ 3C= £2.25, you have D= £2.25- 3C. Putting that into P+ 4D+ 10C= £10.89, we have P+ 4(£2.25- 3C)+ 10C= P+ £9.00- 12C+ 10C= £10.89 so that P- 2C= £1.89 and then P= 2C+ £1.89.When I subtract one from the other I get: 1D + 3C = £2.25
How do I get the prices for 1 large tub of popcorn, 1 fizzy drink and 1 packet of crisps from there??
Many thanks for any help.
Since you have only two equations with three unknown values, this is the best you can do: write P and D in terms of C. Of course, since, as romsek said, the prices must be integer numbers of pence, you could start with C= 0.01, C= 0.02, .... and increase from there.
Hello, Natasha1!
1 popcorn, 4 drinks and 10 crisps cost $10.89.
1 popcorn, 3 drinks and 7 crisps cost $8.64.
How much is 1 popcorn, 1 drink and 1 crisp?
We have: .
Subtract [1] - [2]: .
Substitute into [1]: .
. . .
Add: .