The speed of the two cars 37.5 m/sec and 22.5 m/sec.
Suppose, the two cars are c1 and c2 respectively whose speed x1 m/sec and x2 m/sec respectively
where x1 > x2 In the case of same direction:
30×1 + 30×2 = 1800 (Perimeter = 1800)
x1 + x2 = 60………… (i’)
Again, in the case of opposite direction: Circular Track
120×1—120×2=1800
x1—x2 = 15————-(ii)
Now, from (i) -— (ii),
x1 = 37.5, and x2 = 22.5
a) 5 TK
b) 6.25 TK
c) 2500 TK
(a)The variable cost per book
Let, variable cost per book = V TK and fixed cost = F Tk
1000 copies printing cost F +1000V = 7500 …..(i)
2500 copies printing cost F + 2500V = 15000 …..(ii)
Now. (ii) – (i)
1500V = 7500
v = 5
c) The fixed cost
Putting value of V in (i)=> F+(1000x 5)=7500
F = 2500
b) The average cost per book
As cost function is linear and F = 2500 and V = 5,
so In printing 2000 books we need = F + 2000V= 2500 + (2000 x 5) = 12500 tk.
Average cost $\frac{12500}{2000}$ = 6.25tk.
20 inches
Suppose, width = w inch
Length = 2w inch
Area = 2w² sqr inch
Again, the new length = (2w + 4) inch and the new wi‘dth = (w — 3) inch
According to question;
2(2W+4+W—3)=62
2(3W + I) = 62
6W + 2 = 62
6W = 60
W = 10
Length of the original rectangle is 2W = 2 x 10
= 20 inches
