11 Plus Exams Forum

Hi,

Can someone help please?

1 burger + 2 drinks = £2.80
2 burger + 5 drink = £6.10

find the cost of a burger
Find the cost of a drink.

I did get the answer after so many attempts.. but is there is an easy way to do this?

thanks
meeraa

meeraa wrote:Hi,

Can someone help please?

1 burger + 2 drinks = £2.80
2 burger + 5 drink = £6.10

find the cost of a burger
Find the cost of a drink.

I did get the answer after so many attempts.. but is there is an easy way to do this?

thanks
meeraa

The way I would do it is to say if 1B+2D = £2.80 then 2B + 4D = £5.60 so the extra D must be 6.10-5.60= 50p. hence 1B=£1.80 ...

2 burger + 5 drinks = £6.10
-1 burger + 2 drinks = £2.80
= 1 burger + 3 drinks =£3.30

1 drink therefore = 50p
1 burger + (£1) = £2.80,
1 burger = £2.80-£1.00
1 burger = £1.80

If 1 burger + 2 drinks is £2.80

then 2 burgers + 4 drinks would be £5.60

therefore if 2 burgers + 5 drinks = £6.10 the extra drink must cost 50p

and then it is easy to work out the rest

For simplicity assume B stands for burger and D stand for drinks:
1) B + 2D = 2.8
2) 2B + 5D = 6.1
***********
Rewrite formula 1 to get B
B = 2.8 -2D
Substitute formula 2 with the B you got above, this will give you:
2(2.8- 2D) + 5D=6.1
get rid of the bracket by multiplying 2
5.6 - 4D+5D=6.1
5.6+D=6.1
D=6.1 -5.6
D=.5 or D=50p
Once you have the value of D, you can insert it either in formula 1 or 2 to find B

B=2.8-2D
B=2.8 - 2(.5)
B=2.8 - 1
B=1.8
B=£1.8 (Put back the currency)

Thank you so much for all the replies....
Now I can see how this can be solved.. (diff ways)..

Thanks again

Meeraa