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:
Step-by-step explanation:
let the percent of found balloons be x
given,
total number of balloons= 70
number of found balloons= 28
according to the question,
x% of 70= 28
x/100 × 70 = 28
x=40
hence 40% of the balloons were found
Answer: m∠ATC = 54°
Step-by-step explanation:
Ok, we know that:
m∠ATB = 20° and m∠BTD = 72°
then we must have that the angle between A and D, is equal to the sum of the angles between A and B, and B and D, or:
m∠ATD = m∠ATB + m∠BTD = 20° + 72° = 92°
Now, we also know that m∠CTD = 38°
And the angle:
m∠ATC will be equal to the angle between A and D, minus the angle between C and D, or:
m∠ATC = m∠ATD - m∠CTD = 92° - 38° = 54°
Scalene,Acute i think it is haha