one 9 in every 10s (like 9, 19, 29, etc) => 10
extra 10 9s in 90 – 99 => 10
thus total 20

lets say there are total x cars, thus
x/10 number of cars are yellow initially.

as yellow car’s percent increases from 1/10th to 1/9th after new car arrives, so new car must be a yellow car.
So we can form this equation

1 + x/10 = (x+1)/9

Now we just need to solve this equation
on multiplying both sides by 9*10 =>
9*10 + 9x = 10x + 10
90 – 10 = 10x – 9x
x = 80

So there were 8 yellow cars initially among a total of 80 cars(i.e. 1/10th)
and a new yellow cars comes making 9 yellow cars in total of 81 cars.(i.e. 1/9th)

So answer to the question is 81. there are a total of 81 cars now.

77 empty bottles= 15 filled bottle+2 empty bottle
15+2 empty bottles=3 filled +2 empty bottles
3+2 empty bottles=1 filled bottle
i.e. total filled bottle are 15+3+1=19

Answer: 88

Solution:
From Equation 1: 3Hen = 6 => 1Hen = 2

From Equation 2: Cat + Hen = 7

=> Cat = 7 – Hen = 7 – 2 = 5

From Equation 3: Horse – Cat = 76 => Horse = 76 + Cat = 76 + 5 = 81

Thus Horse + Cat + Hen = 81 + 5 + 2 = 88

Answer: 81

Explanation:
from first equation red flower = 20
from second equation blow flower = (30 – 20)/2 = 5
from third equation 5 – 2yelloflower = 3 => yello flower = (5-3)/2 = 1

Thus Yellow flower + Red flower*(Blue Flower with four petals)

yes thats the catch, blue flower with 4 petals should be of value 4
= 1 + 20 *4 = 81, remember BODMAS rule, multiplication first.