To do this you times 3 by 4 and add it on to the numerator of the fraction, to turn it into a top heavy fraction:
3*4 = 12
1+12/3 = 13/3
Then you multiply the numerator by 21 to work out what 21 times the fraction is:
13*21/3 = 273/3
Then you can divide 273 by 3 to get the final answer:
273/3 = 91
He will have 91 peaches overall.
Hope this helps! :)
