Answer:
no money left (0$), but no extra payment either.
Step-by-step explanation:
x = price per kg of crab
y = price per prawn
if he orders the first list, we know $12 will be left on his card, that means the order costs 100 - 12 = $88.
1×x + 4×y = 88
for the second list we know he would have to pay $28 extra, in addition to the $100 in the card.
so, 100 + 28 = $128
2×x + 2×y = 128
x + y = 64
now we have a system of 2 equations with 2 variables. we use one equation to express one variable by the other, and that we use then in the second equation to solve it.
x = 64 - y
(64 - y) + 4y = 88
64 + 3y = 88
3y = 24
y = 24/3 = $8
=>
x = 64 - y = 64 - 8 = $56
so, if he orders 1.5 kg of crab and 2 prawns we get a cost
1.5×56 + 2×8 = 84 + 16 = $100
so, he will not have any money left in the card, but he will not have to pay anything extra either.
Y=3y=26-6
4y=20
y=5
There you gop
Answer:
Step-by-step explanation:
If you can mow a lawn in 2 hours, then you get 1/2 of the job done in 1 hour.
If your friend can mow the same lawn in 3 hours, then he can get 1/3 of the job done in 1 hour.
The equation for the time it would take for both of you to do the job together, then, is
where x is the number of hours it takes for both of you to do this job. Get rid of the denominators to solve for x. Do this by multiplying everything by the LCD, which is 6x.
which simplifies to
3x + 2x = 6 and
5x = 6
x = 6/5 or 1 1/5 hours
