2^x=4096
i know the answer but i forgot the step how to do them can some one

Scores on a university exam are normally distributed with a mean of 78 and a standard deviation of 8. the professor teaching the class declares that a score of 70 or higher is required for a grade of at least “c.” using the 68-95-99.7 rule, what percentage of students failed to earn a grade of at least “c”?

Paco orders an ice cream for $1, but realizes his wallet is at home and he only has 3/20 of $1 with him. if his mom pays the remaining 7/20 of the dollar, how much will she pay? $0.05 $0.15 $0.85 $0.95

At the beginning of the year, adrian's savings account balance was \$28$28. each week, he deposits another \$15$15 into that account, and he doesn't spend any of his savings. is his savings account balance proportional to the number of weeks since the start of the year?