What is the value of k in the equation 10k-7=7k-15

(least common multiples) the answer that i had in the 1st step was lcm of airline tickets sold=72. idk if that even matters but just in case. ! three co-workers are busy selling airline tickets over the phone. in an 8-hour day, charles can sell 8 airline tickets, ann can sell 9 airline tickets, and michelle can sell 6 airline tickets. step 2 of 2: what is the smallest number of 8-hour days needed for each of them to achieve the same number of sales? it takes charles . it takes . it takes .

Ricky takes out a $31,800 student loan to pay his expenses while he is in college. after graduation, he will begin making payments of $190.66 per month for the next 30 years to pay off the loan. how much more will ricky end up paying for the loan than the original value of $31,800? ricky will end up paying $ more than he borrowed to pay off the loan.

If you could answer these your a life saver