name
Let the number of males be given the name M.
Let the number of females be given the name F.
If 15 females are absent, then M will be twice that of
present females.
This means that M = 2 * (F – 15)
M = 2 * F – 30.
or 2 * F – M = 30.
Now if in addition to the 15 females being absent, we also
have 45 males being absent,
then this gives the equation,
(F – 15) = 5 * (M – 45)
which simplifies to
F – 15 = 5 * M – 225
5 * M – F = 210
Pulling the equations together, we get
5 * M – F = 210
-M + 2 * F = 30
Multiply the first equation by 2, and keep the second
equation as is.
10 * M – 2 * F = 420
– M + 2 * F = 30
Add the equations.
9 * M = 450
M = 50
Verify answer.
Calculate F
from – M + 2 * F = 30
-50 + 2 * F = 30
2 * F = 30 + 50
F = 40.
If 15 females are absent, then number of males will be twice
that of females.
40 – 15 = 25.
50 = 2 * 25. Confirmed.
If also 45 males were absent, then female strength would be
5 times that of males.
Female strength is 25 due to the 15 females being absent.
50 – 45 = 5.
25 = 5 * 5. Confirmed.
3 minutes
127.179(app)
given distance of the train along the wind is 695
and againt the wind is 498
and time = distance/speed
as we know that time is equal in both the cases hence equate
695/s1=498/s2———–(1);
where s1=speed of the plane + speed of the wind
and s2=speed of the plane -speed of the wind
given that speed of the wind is 21k/h
s1=sp+21
s2=sp-21
substitu in eq 1
we get the answer as 27.17(app)
350m
35 hours
17,19,23,29
Before Swapping
_ _ _ _ _ _ _ Shilpa ……..Reena _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
After Swapping
_ _ _ _ _ _ _ Reena _ _ _ _ _ Shilpa _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
—————————–>14=17 <——————————-
So total number of girls in that row are 30
Answer: Option D
Explanation:
As Bob is sitting between Charles and Elena and Douglas is sitting to the left of Elena. We get the following arrangement.
Andy is opposite Bob. Therefore, the final arrangement is as follows.
Fred will be sitting right of Charles if each person interchange his/her place with the person sitting opposite them.
( e ) None of these
0,8x= y
y – 0,7y = 270
y= 270 / 0,3
y=900
0,8x=900
x=1125