(a)[1]
State an expression, in kilograms, for the mass of apples that Mina gets.
(b)[4]
The cost of pears is $40$ cents per kilogram higher than the cost of apples. Mina spends $\$9$ on pears. The mass of pears Mina receives is $0.75\,\text{kg}$ less than the mass of apples. Form an equation in $x$ and show that it simplifies to $x^2 + 40x - 48000 = 0$.
(c)[3]
Solve the equation $x^2 + 40x - 48000 = 0$. Show your working.
(d)[2]
Narinder buys $1.5\,\text{kg}$ of apples and $0.8\,\text{kg}$ of pears. Find the total amount he pays in dollars.