Answer:
Age of younger brother is 4 years..
And age if elder brother is 14 years.
Step-by-step explanation:
Let us denote 'x' as the age of smaller brother,
then, the age of younger brother will be x+10 years.
x+x+10 = 18
2x+10 = 18
2x = 18-10
2x = 8
x = 8/2
x = 4
Age of younger brother is 4 years.
Age of elder brother = x + 10
= 4 + 10
= 14 years.
Answer:
she will need to get a 100 on the fourth test
Step-by-step explanation:
(252+x)/4 = 88
252+x = 352
x = 100
Answer:
8190 ways
Step-by-step explanation:
Given


Selection


Required
Number of ways of selection
4 students can be selected from 15 students in:

Similarly.
5 teachers can be selected from 6 teachers in:

So, the required number of selection is:

Apply combination formula:







Subtract the faster speed:
721.6 - 8.4 = 713.2
Divide by 2 trains:
713.2/2 = 356.6
The slower train is going 356.6 miles per hour.
The faster train is going 356.6 + 8.4 = 365 miles per hour.
Y= x2+2 is the correct answer