Answer:
$11.13
Step-by-step explanation:
$7.00 + $3.50 = $10.50
6% of $10.50 is $0.63
$10.50 + 0.63 = $11.13
50kg
K = Keith B = Beth H = Henry
K = 20 + B
H = 2B - 30
K = H
20 + B = 2B - 30
B = 50kg