5 (a) Emma saves £1 coins and £2 coins.
She has twice as many £1 coins as £2 coins.
She has saved exactly £100
How many £2 coins does she have?
12 marks
Answer

25

Step-by-step explanation:

25 2 euro coins*2=50

50 1 euro coins*1=50

50+50=100

25

Step-by-step explanation:

We can have a set of equations for this. Let x be the number of 1 pound coins and y be the number of 2 pound coins.

We can set an equation like this:

Since she has twice as many 1 pound than 2 pound coins, we can set this equation:

x=2y

Since the worth of the coins add up to 100:

(1 pound)*x+(2 pounds)*y=100pounds

x+2y=100

We can substitute x=2y

2y+2y=100

y=25

Therefore we have 25 2 pound coins

probability for j is 1/4

while

a is 1/6

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