Let's let the weight of a large box be L, and the weight of a small box be S.

We know that 5 large boxes and 3 small boxes is 120kg, so:
5L + 3S = 120

We also know that 7 large boxes and 9 small boxes is 234kg, so:
7L + 9S = 234

You can multiply the first equation by 3 to get:
15L + 9S = 360

See how now both equations have 9S? We can now subtract one from the other:
(15L+9S) - (7L+9S) = 360-234
8L = 126
L = 15.75

Now sub this value back into an equation:
(5x15.75) + 3S = 120
3S = 41.25
S = 13.75

Double check these values
(7x15.75) + (9x13.75)
= 110.25 + 123.75
=234, which is consistent with above.

So a large box is 15.75kg, and a small box is 13.75kg.

Hope this helped

5 0

2 years ago

Three quarters of the batch of twenty cookies burned when you forgot to take them out of the oven how many cookies burned

Natali5045456 [20]

15 cookies burned because if you Turn $\frac{3}{4}$ into a decimal then multiply it by 20 you get 15 and thats your answer.