Two heavyweight boxers decide that they would achieve better results if they entered a lighter weight class. For each boxer, this means a total loss of 13 kg. By the end of week 1, each has lost 1 kg, and in every later week their weight loss is a little smaller than in the week before. Boxer $A$ loses 0.98 kg in week 2. It is stated that his weekly weight loss is in arithmetic progression.
(i)[1]
State an expression for his overall weight loss after $x$ weeks.
(ii)[2]
He attains his 13 kg target in week $n$. Use your result from part (i) to determine the value of $n$.
(iii)[4]
Boxer $B$ loses 0.92 kg in week 2 and it is stated that his weekly weight loss is a geometric progression. Calculate his total weight loss after 20 weeks and show that he can never achieve his target.
(c)[4]
Calculate his total weight loss after $20$ weeks and show that he can never achieve his target.
Worked solution & mark scheme
This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: “A suitable expression, for example $1.01x-0.01x^2$” …