Help! For 30 points!

What is the value of
expressed in base 10?

Would really appreciate if you explained how the answer works as well.

98 point question what is the record for most points in one

Askateboard ramp is in the shape of a right triangle what is the height of the ramp

In a certain city, the hourly wage of workers on temporary employment contracts is normally distributed. the mean is $15 and the standard deviation is $3. what percentage of temporary workers earn less than $12 per hour? a. 6% b. 16% c. 26% d. 36%