Since participants have an equal chance of receiving one of the three types of coupons (skiing, snow tubing, or sleigh rides), each type of coupon has a probability of \( \frac{1}{3} \).
To find the expected number of participants who would receive a coupon for sleigh rides, you can multiply the total number of participants (900) by the probability of receiving a sleigh ride coupon:
\[ \text{Expected number of sleigh ride coupons} = 900 \times \frac{1}{3} = 300 \]
Therefore, the expected number of participants who would receive a coupon for sleigh rides is 300.