I will give brainliest and 5 stars if you help ASAP

£39.20

Step-by-step explanation:

→ Identify which ratio goes to each person

2 : 1 : 5

2 = Paul

1 = Colin

5 = Brian

→ Divide the total tip by the total sum of the ratio's

£78.40 ÷ ( 2 + 1 + 5 ) ⇔ £78.40 ÷ 8 = £9.80

→ Now we know one part is equal to £9.80 we multiply this number by each of the associated ratio's

Paul = £9.80 × 2 ⇔ £19.60

Colin = £9.80 × 1 ⇔ £9.80

Brian = £9.80 × 5 ⇔ £49

→ Minus Brian's tip against Colin's tip

£49 - £9.80 = £39.20

set each factor equal to 0

4x-3 = 0

2x-1 = 0

solve for x.

4x-3=0

4x=3

x= 3/4

solve for x. 

2x-1= 0

2x= 1

x= 1/2

eventually after a few more steps, your answer should be 1/2 is less than or equal to x and 3/4 is greater than or equal to x