Can anyone help me out with this question?

2 varieties of rice are mixed in the proportion 3: 4, and the mixture is sold at Rs 28/Kg at 40% profit. If the 2nd variety of rice costs Rs 3 more than the 1st variety of rice, find the cost price of the 1st variety of rice?

The objective of giving the profit is to determine the cost of the mixed rice.
with 40% profit at Rs 28 selling price, the cost amounts to Rs 20 per kg.

the two varieties of rice are mixed in 3:4 proportions. So a KG of rice should have also have similar proportions.
cost of the mixed rice per kg = (proportion of first rice)*(cost of first rice per kg)+(proportion of second rice) (cost of second rice per kg )
x => cost of the first rice

20 = (3/7)(x) + (4/7)(x+3)
20 = (3x+4x+12)/7
128 = 7x
x = 18.28571…

Ram and Suraj start running from point A on a circular track of 1,200 m. Ram runs at a speed of 12 km/hr and Suraj at a speed of 8 km/hr. They start running in opposite directions at the same time. When each of them reaches at point A for the first time, they reverse their directions along the track. If in stead of reversing the directions on reaching A, they reverse the directions when they meet each other, how much time after starting from A, they will meet for the second time?

a. 5.4 min

b. 7.2 min

c. 10.8 min

d. 11.2 min

e. 8.2 min

MRP (with 40% profit is given)
i.e. CP is -40% of 28 hence
CP x 1.4 = 28
CP = 28 x 10/14 = ₹20

20 = (3x/7) + 4/7 (x+3)
20= 3x/7 + 4x+12/7
20-12= 7x/7
x=8 and hence x+3 = 11

To cross check your answer
20-11 = 9 and 20-8= 12 when you divide by 3 you get the ratio 3:4
Hope this helps!