Agirl had 20 coins in nickels and dimes whose sum was $1.40. she spent 65cents , using 8 coins. she now has ? nickels.

9 Nickles

Step-by-step explanation:

Let n = number of nickles and d = number of dimes

d + n = 20 -----------(1)     [ total number of coins 20 ]

Dimes = $0.10

Nickles = $0.05

0.1d + 0.05n = $1.40 ---------- (2)         [20 coins worth $1.40]

Since d + n = 20

∴ n = 20 - d

Let's substitute n in equation (2)

0.1d + 0.05(20-d) = 1.40

0.1d + 1 - 0.05d  = 1.40

0.1d + 0.05d = 1.40 - 1

0.05d = 0.4

d =

d = 8

Now put value of d in equation (1)

n + 8 = 20

n = 20 - 8

n = 12

Let's check 8(0.1) + 12(0.05)  = $1.40

Now she spent 65 cents using 8 coins.

The only combination of 8 coins worth $0.65 is

5d + 3n = $0.65

Hence, she used 5 dimes and 3 nickles.

Now she has 12 - 3 = 9 Nickles

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.