c
12
Perimeter of semi circular = πr+2r
Where r is radius , π = 22/7
πr+2r= 144 (given)
(22/7)r +2r = 144
22r+14r = 144*7 (multiply both sides by 7)
36r = 144*7
r= 144*7/36 = 28
radius =28 cm
Area =( 1/2)πr^2
Area=( 1/2 )*(22/7)*28*28
= 1232cm^2
Ans : area is 1232 cm^2
b
Take 5 pills from jar 1, 4 pills from jar2,…. and 1 pill
from jar 5 and put altogether in the scale. the ideal
weight should be (1+2+3+4+5)x10= 150gms. for eg if the jar2
is contaminated then the weight will be 146 gms. so
depending on the amount of weight loss we can identify the
contaminated jar.
Which means the train will travel 180 m in 6 seconds so
We need to convert this into minutes
6×10 = 60s= 1 minute.
180×10 = 1800 m train will travel 1.8 km in 1 minute.
1.8×60 = 108 kmph
choosing my career path
maternal grand mother
let first digit be ‘X’
then 5th digit is ‘3X’
let 2nd digit be ‘Y’
then 3rd digit is ‘Y-3’
and 4th digit is ‘Y+4’
then the no is ‘(X)(Y)(Y-3)(Y+4)(3X)’
from the above we can say 3X<=9
so X<=3 and any of the digit in the number is <=9
and also given that 3 pairs sum is 11...
so make trial and error..
if X=1...any of the no is 10 which is wrong trial....
if X=2...then let Y+4=9 ==> Y=5
then no is 25296
first pair 2+9=11
second pair 2+9=11
third pair 5+6=11
now the answer is 25296
RABBIT
b
1:9
The first number is 36
Step-by-step explanation:
let their common factor be ‘x’
hence,
the ratio be 3x/5x
hence, by condition;
(3x-9)/(5x-9)=9/17 ch upu
9(5x-9)=17(3x-9)
45x-81=51x-153
153-81=51x-45x
72=6x
x=72/6
x=12
the first number is 3x=3×12=36
Put switch 1 on and leave it on for 2 minutes, then switch it off.
Put switch 2 on and leave it on, then walk into the room.
If the light is on, the answer is switch 2.
If the light is off but the bulb is warm when you feel it, the answer is switch 1.
If the light is off and the bulb is cold when you feel it, the answer is switch 3.
let no of boys in group is = x
then total sum = 30 * x
after joining one more boys with a weight of 35 kg the total sum is = 30x + 35
after joining the new student the weight will increase 1 kg
so total sum
30x + 35 = 31(x+1)
x = 4
Monday =y cheques
Tuesday =3y cheques
wednesday=4000 cheques
totaling to 16000 cheques
therefore y+3y+4000=16000 cheques
4y+4000=16000 cheques therefore 4y=16000-4000 cheques= 4y=12000cheques
therefore y=12000/4=3000 cheques
monday=3000 cheques
tuesday=3×3000=9000cheques
( c ) 10
150m