Sonali Bank Officer (IT)
Written Math Solution :
1) The salaries of Lamia and Farzin are in the ratio 7:5 and the total of their salaries is Tk 12000. If their annual increments are Tk 200 and Tk.150 respectively, what will be the ratio of their salaries after one year?
Solution : Let, L = 7x F= 5x A/Q, 7x+5x = 12000 12x = 12000 x = 1000 So, 7x= 7*1000 = 7000 5x = 5*1000 = 5000 Now, required ratio = (7000+200): (5000+150) = 7200: 5150 = 144:103
Answer: 144:103
2) A man goes upstream at 10 km/hr to a place and back down stream to same point at 6 km/ hr. what is the average speed in the journey?
Solution : Average speed = (2*6*10)/(10+6)=7.5
Ans : 7.5 km/hr
3) A man is standing on a railway bridge which is 180 m long. He finds that a train crosses the bridge in 20 seconds but himself in 8 seconds. Find the length of the train.
Solution : let, lengh of the train x now, x/8 = x+ 180/20 ( Considering, Speed equal in both case) hence solving equation x = 120 speed = 120/8* 18/5 = 54
Ans : 120 m and 54 kmph
4) The sum of ages of the Father and Son is 50 years. when the ages of the son will be equal to the present age of the father, the sum of their ages will be 102 years. Find the age of Father and Son?
Solution : Let, Age of Father = X Age of Son = 50-x Again, When age of son will x, the age of father will = x + ( X - (50-x)) = 3x -50 Now, 3x-50+ x = 102 x = 38 Father's age = 38 Son's age = 50-38 = 12
5) By selling a table for tk 39, gain is as much as percent as its cost. What is cost price?
Solution : 5) Suppose, Cost price = x Gain = x% atq, x+x%of x = 39 x+x^2/100 = 39 100x+x^2 = 3900 x^2+100x-3900 = 0 x^2+130x-30x -3900= 0 (x+130)(x-30) = 0 x= -130 ( price can't be negative) or , X= 30
Answer: 30 taka