On a journey across Delhi, a taxi average 30 kmph for 60% of the distance, 20 kmph for 20% of it and 10 kmph for the remainder, the average speed for the whole journey is?

sum of odd number upto 100 = 1 + 3 + 5 + 7+....+ 95 + 97 + 99
=(1+99) + (3+97) + (5+95) +.... upto 25 terms
= 100 + 100 + 100 +.... upto 25 terms
= 2500

Average = 2500 /50
= 50

Age of A : age of B : age of C = 3 : 5 : 7
So the average age of 3 boys (3x + 5x + 7x ) /3 = 15
?15x= 15 x 3
? x= 3

Average cost =( w₁x₁ + w₂x₂ + w₃x₃ ) / (w₁ +w₂ +w₃)

= ( 1200 x 30 +1500 x 25 + 2000 x 32) / ( 1200 + 1500 + 2000 )
= 137500 / 4700
= ? 29.25 per kg

a + b + c = 11 x 3 = 33 .....(i)
c + d + e = 17 x 3 = 51 .....(ii)
e + f = 22 x 2 = 44 .....(iii)
e + c = 17 x 2 = 34 .....(iv)

From Eqs. (ii) and (iv), we get
34 + d = 51
? d = 17

Now adding Eqs. (i), (ii), (v), we get
a + b + c + d + e + f = 33 + 44 + 17 = 94
? Average of a, b, c, d, e and f = 94/6 = 15²?₃

Sum of the ages of 4 men five years ago
= 48 x 4
=192 yr

And sum of present ages of the four men
= 192 + 5 x 4
= 212 yr

Now ( 212 + Age of the new man ) / 5 = 50
? Age of the new man = 50 x 5 - 212
= 38 yr.

Let total journey be y km.
From question y/35 - y/40= 15/60
? y = ( 35 x 40 )/ ( 4 x 5 ) = 70
? Total Journey = 70 km

New sum of numbers = previous sum - 26 + 36
=10 x 15 - 26 + 36
= 160
? Correct Average = 160 / 10 = 16.

Seventh Result = sum of first 7 results + sum of last 7 results - sum of all 13 results.
? Seventh Result = (7 x 63) + (7 x 70) - (13 x 68 )
=47

Thirteenth Result = sum of all 25 results - sum of first 12 results - sum of last 12 results.
= 25 x 18 - 12 x 14 ? 12 x 17
=78

From question
M + T + W + TH = 4 x 38° = 152°
? T + W + TH =152° ? 30° = 122°

Again from question
? T + W + TH + F = 4 x 40° = 160°
? F = 160° ? 122°
= 38°