Carol sold twice as many magazine subscriptions as jennifer. if carol and jennifer sold 90 subscriptions in all, how many subscriptions did carol sell? 45 90 30 60

I'm at a bookstore with $\$35$ in my pocket and a $20\%$-off coupon. what is the cost of the most expensive book i can buy with my money and the coupon? (assume that there are books of every possible price in the bookstore. it's a large bookstore! )

Either enter an exact answer in terms of \piπ or use 3.143.14 for \piπ and enter your answer as a decimal.

Write the equations in logarithmic form 7^3=343