AOA
Are u sure that the statements and options in 1st three questions are right?

Please check the solutions and tel me about my mistakes specially senior members

4. A batsman has a certain average of runs for 11 innings. In the 12 th inning he scores 129 runs, thereby increasing his average by 9 runs. What is his average for the first 11 innings?
Solution:
let average of 11 innings b x
then
player got x for 11 times
and 129 for one time
so average is
(11x+129)/12 which is greter than x by 9
=>(11x+129)/12 =x+9
=>11x+129=12x+108
=>x=21

5. A and B enterd into a partnership invseting rs. 12000 and rs. 15000 respectively.B was also a working partner and got 25% of the profit for their work.what was the total profit in rupees, if a got rs.8000 as his share?
Solution:
let B has got share x
then
ratio b/w investments of A & B = ratio b/w their share
=>12000/15000=8000/x
=>x=10000
total price they got on the basis of investments is 10000+8000=18000
if B gets 25% of total profit on being active member then the amount of 18000 is 75% of total profit so
profit=18000*100/75=24000

6) A shopkeeper sold an electric iron at 10% profit. Had he sold an iron at 20% profit, he would have gain rs.%) more. The cost price of the fan was:
Solution:
if x is original price then
the cost price with 10% profit is x+.1x
and with 20% profit is x.2x which is 96Rs. more than with the 10% profit
=>x+.2x=x+.1x+96
=>x=960 Rs.

5) a goods train left Lahore for Multan at an average speed of 45KM/HR.five hour later an express train left the same station at an average speed of 60 km/ hr following the goods tarain on the parallel track. How far from Lahore did the express train overtake the goods train?
Solution:
let that distance coverd b x
then time taken by goods train to cover it is=x/45 hrs
and by express to cover it is x/60 hrs
express is started 5 hrs late so
x/45=x/60+5
=>4x=900+3x
=>x=900 km

6)a man can row 30 km downstream and 18 km upstream each in 3 hours.the speed of the boat in still water is:
Solution:
downstream
in 3 hrs distance =30 km
so speed is 10 km/hr
upstream
in 3 hrs distance =18 km
so speed is 6 km/hr
so in still wter speed will b the average of both the speeds which is
(6+10)/2km/hr
i.e. 8 km/hr