Pippa owns a snack bar. She uses
of a kilogram of spread each day.
Spread costs £3.20 for a 1 kilogram tub and £6.15 for a 2 kilogram tub.
Pippa buys enough spread to last for 14 days.
What is the lowest price Pippa can buy this spread for?

£43.05 (I believe, refer to step-by-step explanation.)

Step-by-step explanation:

Let's compare both of these tubs if we were to buy either of them for 14 days.

Starting with the 1 kilogram tub we need to do the calculation:

£3.20 × 14 = £44.80

(Type 3.2×14 into your calculator or write on paper this way to calculate.)

Now let's do the 2 kilogram tub.

£6.15 × 7 = £43.05

(Type 6.15×7 into your calculator or write on paper this way to calculate.)

The reason why I have put 7 instead of 14 is because it is 2 kilograms. Since Pippa uses 1 kilogram per day, you only need to buy 7. 2 × 7 = 14

So comparing either of these prices, buying 7 2-kilogram tubs is much cheaper compared to the 14 1-kilogram tubs.

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18