The answer is 52
x - the number of students in a bus
4 + 9x = 472
9x = 472 - 4
9x = 468
x = 468 / 9
x = 52
Step 2 , supposed to be 4^-15 instead of 4^-2. Always multiply the exponents together.
Answer: Chris made a mistake in step 2 -C
(x-3)(x+4). -3,4 multiply to -12, and add to get 1
Here the two samples should be comparable .
The total number of cows in the farm = 200
the total number of cows giving milk = 150
the total number of cows in corral = 20
Suppose total number of cows giving milk in corral = x
The ratio of the total number of cows present to the total number of cows giving milk should be same in farm and corral
so : 200 = 20
------- -------
150 x
now we do cross multiplication :
200 x = 150* 20
200x = 3000
x= 3000/200
x= 15
SO we expect 15 cows in corral should be giving milk .
Answer : 15