4.5 is the answer
Divide 49 from both sides
220.5 / 49 = 4.5
5x+2y=20
Substitute 0.3 for x
5(0.3)+2y=20
Multiply 5 by 0.3
1.5+2y=20
Subtract 1.5 from both sides
2y=18.5
Divide 2 on both sides
Final Answer: y= 9.25
Answer:

where x = number of adults
y = number of children
and the extra weights of 4kg of each person.
80 goes into 142 once, so one is our whole number. there are still 62 / 80 left, so we reduce this fraction. The answer is
1