X = 1/2 * b*h
base incresed by 4 times & height
is devided by 2
X = 1/2 * 4b * h/2
X = h/4 * 4b
X = hb
2nd
The first 10 odd prime numbers are 3, 5, 7, 11, 13, 17, 19, 23, 29 and 31.
Sum of the odd prime numbers = (3+5+7+11+13+17+19+23+29+31)
= 158
Number of odd prime numbers = 10
We know, Average = (sum of the 10 odd prime numbers ÷ Number of odd
prime numbers)
Average =
= 15.8
∴ The Average of first 10 prime numbers which are odd is 15.8
3, 7, 15, 27, 63, 127, 255
B. 27
( Number × 2 ) + 1
3 × 2 + 1 = 7
7 × 2 + 1 = 15
15 × 2 + 1 = 31 ( not 27 )
31 × 2 + 1 = 63
63 × 2 + 1 = 127
127 × 2 + 1 = 255
13 Kigs & 6 Libs –> 510tors in 10hrs
” –> 51 tors/hr
14 Libs –> 484 tors in 12hrs
” –> 121/3 tors/hr
1 Lib –> 121/42 tors/hr
==> 6 Libs –> 121/7 tors/hr
Now,
13 kigs and 6 Libs –> 51 tors/hr
Only 13 Kigs –> 51 – (121/7) tors/hr
= 236/91 tors/hr
150
petticoat
Length of train = 125Mtrs
Speed of man = 5Km/Hr
=(5*1000)/(1*3600)
=1.4M/s
Time taken for train to pass = 10s
Spd = D/T
Total Distance (Man distance+ Train Length)
#Distance covered by Man in 10s
D=Spd*T
= (1.4M/s*10s)
= 14Mtrs
#Train length = 125Mtrs
Total D = 14Mtrs + 125Mtrs
= 139Mtrs
Time taken = 10s
Sp = D/t
=139M/10s
=13.9M/s
Speed of Stream = 1/2 (Downstream Speed – Upstream Speed)
=1/2(40-14)
=1/2(26)
=13km/h
method 2:
for down stream case :speed=Boat speed + Stream speed
for up stream case :speed=Boat speed – Stream speed
therefore, Bs + Ss =40
Bs – Ss =14
(-) (-) (-)
———————
2Ss=26
Ss=26/2 = 13Km/h
Stream speed= 13Km/hr
264
28
to arrange m objects in n places => nCm
i.e. for this example m=2(+,- sign) and n = 8(places between two number from 1 to 9)
SO, answer is : 8C2 = (8*7) / 2 = 28