A pizza had 9/10 left before Lucas ate 4/5 of the pizza. How much pizza is left over? of a pizza

Step-by-step explanation:

always try to bring fractions you need to compare to the same denominator (bottom number).

we have 9/10 of the pizza left.

then 4/5 if the pizza are eaten.

how to compare 9/10 with 4/5 ?

by bringing 4/5 also to a fraction of 10ths.

what do I need to multiply 5 with to get 10 ?

right, 2.

since we don't want to change the overall value of the original fraction, we need to multiply both levels (numerator and denominator) by that same factor :

4/5 × 2/2 = 8/10

aha !

that we can compare with 9/10.

so, when Lucas ate 4/5 (= 8/10) of the pizza, when there was originally 9/10 left, then we have 1/10 of the pizza left.

step-by-step explanation: so we look at the formula un = a + (n-1)d

un is the amount of seats

n is the nth term aka row number

a is the original sequence/row number

d is the difference between each term

so in this a=22 d=6 and n can remain as n because we are simply formjng a rule

lets put these in the equation

un=22+(n-1)(6)

this is your answer to part a

however

lets double check that this is correct, we'll try putting it into the second term

un=a+(n-1)d

u2=22+(2-1)(6)

u2=22+6

u2=28

as the question said the second row has 28 seats so now we know the formula we made is correct.

as for part b

un=a+(n-1)

its asking us to find a row with 100 seats.

remember un was the amount of seata so all we do is substitute this in.

un=100 a=22 d=6

un=a+(n-1)d

100=22+(n-1)(6)

so now we simplify to find n which is the row number.

100-22=22+(n-1)(6)-22

78=(n-1)(6)

78/6=(n-1)(6)/6

13=n-1

13+1=n-1+1

14=n

so now we know that in the 14th row there is 100 seats.

hope this and that you understood! its my first time using the app or anyone out on here : p its also me to revise so a bunch! ask more questions if you dont understand ☺