Colin, Sara and Gordon share some sweets in the ratio 5:2:1. Colin gets 36 more sweets than Gordon. How many sweets are there altogether?

notes:

c= Colin

s=Sara

g=Gordon

c=g+36 (1)

c : g

5 : 1

c/g=5

c=g*5 (2)

=> from statement (1) => g*5=g+36

5g-g=36

4g=36

g=36/4=9 g=9 sweets

=> from statement (2)=>c=5*9=45 c=45 sweets

s : g

2 : 1

=>s/g=2/1

=> s=2g

s=2*9 s=18 sweets

sum=c+s+g

sum=45+18+9=72 sweets

its definatley   this on your answer choice?