Question

a man borrows rupees 750 at 10% for and 1 rupees 1200 at 8% per annum and mm at 6% per annum find the total interest paid by him in 4 years also find the total sum borrowed and the total amount the man has to pay at the end of 4 years to clear his debit

Answer 1

by the formula 
I= (P×R×T)÷100
interst in 
1st case =rs 300
2nd case =rs 384
3rd case i could not understand what is mm?