Problema Solution
Tony was still 14 years old on Wednesday, September 9. Exactly three weeks ago he said his birthday was in 40 days. On what day of the week will Tony be 16 years old? (No leap year is involved)
Answer provided by our tutors
lets find the birthday of Tony
September 9, Wednesday - he has 14 yo
3 weeks ago will be 3*7 = 21 day before
since August has 31 day
September 9 - 21 = 31 - 12 = August 19
August 19, Wednesday - he was 14 yo
August 19 + 40 days = 19 + 5*7 + 5 = September 28, Monday
September 28, Monday - Tony's 15teenth birthday
next year he will be 16 and since it is not a leap year the year has 365 days
365 = 52*7 + 1
thus the 16teenth birthday will be on Tuesday.