The answer is x times 7 or 7x.
Answer:
Now: 6 yr mean age
in 10 yrs? 16 yr mean age
in 20 yrs? 26 yr mean age
Why? Because regardless of the relationship between each sibling's age, your always adding the 10yrs to each individual, which you are then dividing out to determine the mean age. See proof below:
Including anita, there are 6 people. We'll define each age as an unknown variable. Assume we know nothing about the relationships between their ages
for example sake
anita's age = a
sister 1's age = b
sister 2's age = c
brother 1's age = d
brother 2's age = e
brother 3's age = f
Now:
mean age = (a + b + c + d + e + f)/(6 people) = 6 yrs
in 10 yrs:
mean age = ((a+10) + (b+10) + (c+10) + (d+10) + (e+10) + (f+10))/(6 people)
mean age = (a + b + c + d + e + f + 60)/(6 people)
mean age = (a + b + c + d + e + f)/(6 people) + (60)/(6 people)
mean age = (a + b + c + d + e + f)/(6 people) + 10
Notice the first term is the same expression of the mean age for "Now"
Thus, in 10 yrs:
mean age = 6 + 10 = 16 yrs
The same principle applies for "x" yrs from now, as long as we know what the mean age is "Now"
3.
m/_QOR + m/_ROS = 90 (because the two angels together make a right angle)
Substitute.
x + 5 + 2x + 7 = 90
3x + 12 = 90
-12 -12
subtract 12 from both sides
3x = 78
Divide each side by 3 to get x by itself
x = 26
4. those two angles in the picture are vertical, which means they're congruent.
with that in mind...the ray makes a right angle on one and the other, w, you dont know. so to get the whole angle you need to add both angles to get the whole thing so...
m/_w + 90 = 125
subtract 90 on both sides
m/_w = 35
Answer:
set mary is x years old, and helen is y years old.
first sentence:x=2y
second one:4(y-8)=x+4
bring x=2y in 4(y-8)=x+4
=>4y-32=2y+4
=>2y=36
=>y=18
=>x=36
mary:36
helen:18