Answer:
120th caller
Explanation:
According to the problem, calculation of the given data are as follows,
$100 bill = 30th caller
Movie tickets = 40th caller
So, to find out first to win both prizes, we will use LCM method,
LCM of 30 and 40 = 10 | 30 , 40
| 3 , 4
LCM of 30 and 40 = 10 × 3 × 4 = 120
Hence, 120th caller will be the first to win both prizes.