图为一个百货商店的抽奖转盘。
指针停在任意扇形区域的可能性相同。
扇形区域分别显示可以赢得的特等奖（GRAND prize）、$5 或$10 礼券，或者是未中奖（MISS）。
顾客在商店每消费 $50 即可获得 1 次旋转机会。

1. Find the probability of landing on a GRAND sector.

There are $2$ GRAND sectors out of $8$ equal sectors.

$P(\text{GRAND})=\frac{2}{8}=\frac{1}{4}$

1. Find the probability of landing on a \$5 or \$10 voucher sector.

There are $3$ sectors labelled $5 and $2$ sectors labelled $10, out of $8$ equal sectors.

$P(\text{\$5 or \$10 voucher})=\frac{3+2}{8}=\frac{5}{8}$

1. Find the number of spins Mrs Singh gets.

Mrs Singh spends $\char36{}120$.

Since each spin is given for every $\char36{}50$ spent,
$120 \div 50 = 2\text{ remainder }20$
So Mrs Singh gets $2$ spins.

2. Find the probability that she wins at least one prize in 2 spins.

A prize means any sector except MISS.

For one spin,
$P(\text{MISS})=\frac{1}{8}$

So for 2 spins,
$P(\text{no prize in both spins})=\frac{1}{8}\times\frac{1}{8}=\frac{1}{64}$

Hence,
$P(\text{at least one prize})=1-\frac{1}{64}=\frac{63}{64}$