1,500+343(3×12)=13,848
1,500+343(36)=13,848
1500+12,348= 13,848
The easiest way, I think, is to convert the mixed number into an improper fraction, then multiply by 3.
3 1/2 = 7/2
7/2 · 3 = 21/2
now just change the improper fraction back to a mixed number by dividing and putting the remainder into fraction form
21/2 = 10 1/2
You could also multiply the whole number by 3 and the fraction by 3, ending up with 9 3/2, but then have to convert the improper fraction into a mixed number
3/2 = 1 1/2
then add the numbers together
9 + 1 1/2 = 10 1/2
either way works, whatever is easiest for you.
A) Gavin’s drinks altogether cost £9.00
1.50+2.50x3
=1.50+7.50
=£9.00
b) Lian gets back £3.50
1.50+2.00+3.00
=6.50
10.00-6.50=£3.50