ANSWER
Group A
Step by step explanation
I am bad at explaining things
If we want to find The group with the youngest age , we have to find the mean. The mean , means that we add up all the numbers ( the age) ,then divide them with how much number you added . For example, we add the age of group A 9+10+10+10+10+10+10+10+15+15+15+15+15+15+15+15+17+17+17+17+17+17+17+17+19+19+19+19+19+19=449
Than Count how many people are in group A , group A have 30 people that the number you will be dividing
So 449 divided by 30 is 14.966
That the average
The same go for group B
10+10+10+10+10+10+14+14+14+14+14+18+18+18+18+18+18+25+25+25+25+25+28+28+28+28+29+29+29+29=519
There 30 peoples in group B
519 divided by 30 is 19.7
So the Average of groupB is 19.7
Group a is 14.9 and group B is 19.7
Group A average is smaller than Group B that means ,The average of Group A is younger than Group B so the answer will be group a
Group A is the younger Group then group B
Bring y to one side and the rest to the other switching the positives to negative then you’ll get Y=114
Answer:
The opposite of a number is its additive inverse. The sum of a number and its opposite is zero. (This is sometimes called the property of opposites ). a+(−a)=0.