Let the marks of the students in class 1 be

the average of these 12 marks is 90, so

which means

similarly, let

be the marks of the students in the second class,
so

which means

The 32 students averaged:
Answer:
2
Step-by-step explanation:
9(x+1)=25+x
9x+9=25+x
9x-x=25-9
8x=16
x=16/8
x=2
You get 3x + 4x, +4- -3,and +3 + 4
Answer:
b 20.6
Step-by-step explanation:
Answer: 
Step-by-step explanation:
Given: A tourist first walked 17km with a speed of v km/h.
Since 
therefore, 
Let
be the time he walked with speed v.
then 
Also he hiked 12 km uphill with the speed that was 2 km/hour less than his original speed.
Let
be the time he hiked 12 km,
Then 
The total time for the whole trip is given by:-

Substitute the values of
and
in the equation, we get
