4) Jessica sold half of her comic books and then bought 8 more. She now has 13. How
many did she begin with?

a) Let her  comic books be x

b) as she sold half it will be

  + 8 = 13  ( as she sold half and then she bought 8 more that means plus and then now she have 13 that means = 13)

c ) to solve to find the books she have we need to

+ 8 = 13

Transpose

 = 13 - 8

= 5

x = 5 × 2

x = 10

the comic books were 10

we can even cross- check to see if the value is right instead of x put 10

+ 8 = 13

5 +8 = 13

13 = 13

Cross-checked

solution:

as, mean is defined as sum of all the observations divided by total number of observations.

and , median is mid value of the data whether arranged in ascending order or descending order.

consider, roadsters:

2,3,4,5,6,7,8,9

mean =

also, median= , because number of observations is even, so median is mean of two mid values.

now, coming to bandits

2,3,4,5,6

mean =  

median = 4, as number of observations is odd.

so, roadsters has greater median as well mean than bandits.

→option a is true about the repairs performed on 2 types of cars:

bandits have lower median and mean than roadsters.

y=mx+b is the final answer!   : )