In a drawer there are only patterned, plain, striped and spotted socks. A sock is taken at random from the drawer. The table shows the probabilities that the sock will be patterned or will be spotted.
| Design | Patterned | Plain | Striped | Spotted |
|---|---|---|---|---|
| Probability | 0.35 | 0.05 |
The probability that the sock will be striped is three times the probability that the sock will be plain. There are 42 patterned socks in the drawer.
Work out the number of striped socks in the drawer.
