4d/15-x = 4
3d/15+x = 2
Divide both,
4(15+x)= 2•3(15-x)
30+2x = 45-3x
5x= 15
Speed of stream = 3 kmph

3x +2y = 150
3y + 2x = 210

6x + 4y = 300
9y + 6x = 630

5y = 330
y = 66

3x = 150 - 132
3x = 18
x = 6

66-6 = 60

x+1 x+3 x+5 x+7 x+9

(x+1)²+(x+3)² x+7)²+(x+9)²
------------------- + -------------------- = 492
2 2

x²+16x+65-x²-4x-5 = 492

12x = 432
x = 36

Smallest = X+1 = 37

25-25-25*25/100 = -6.25%

300/75% - 300/125% = 160

A : c
4 : 5 (tym)
5 : 4 (eff)

Tw=60b

60b/9 -60b/(9+b) =5

b/(81+9b) =1/12b

12b^2=9b+81
4b^2-3b-27=0

B=3
By c=60*3/4 =45 ✔

600=b*2b*2/b

B=150 kmph

Tym by b=600/150 =4 hr
Tym by a=6 hr
Speed of A=600/6 =100kmph ✔

do with ratio method

3 4
3 4
———-
9 16
9 == 67.5
16 == 120

S) 4 5
T) 5 4
1 == 36
5 == 180
12*3 == 36km
36*5/48 == 3hr 45min

50/(20*5/18)= 9 sec
4 mins 9 sec = 249 secs by Group B
125/(25*5/18)= 18 sec
4 mins - 18 sec = 222 secs after increase

249 : 222 time
222 : 249 speed

27/222= 12.16% ~ 12.15% ans solved by someone

Int=4800/4 =1200
1200=p*R/100
Pr=120000
P=120000/r
A=p(1+r/100)^2 .....1
Put value of p in 1..
14520 =12(100+r)^2/r

R^2-1010r+10000=0
R=10%✔