Kay has 35 and Kim have 20
Amount financed
320−100=220
Total paid
100+25×12=400
Interest paid
400−320=80
Interest rate=(2yc)÷(m (n+1))
I=(2×12×80)÷(220 (12+1))
I=(2×12×80)÷(220×13)
I=0.67×100
I=67%
18. If f(x)=[xsin πx] {where [x] denotes greatest integer function}, then f(x) is:
since x denotes the greatest integers which could the negative or the positive values, also x has a domain of all real numbers, and has no discontinuous point, then x is continuous in (-1,0).
Answer: B]
20. Given that g(x)=1/(x^2+x-1) and f(x)=1/(x-3), then to evaluate the discontinuous point in g(f(x)) we consider the denominator of g(x) and f(x). g(x) has no discontinuous point while f(x) is continuous at all points but x=3. Hence we shall say that g(f(x)) will also be discontinuous at x=3. Hence the answer is:
C] 3
21. Given that f(x)=[tan² x] where [.] is greatest integer function, from this we can see that tan x is continuous at all points apart from the point 180x+90, where x=0,1,2,3....
This implies that since some points are not continuous, then the limit does not exist.
Answer is:
A]
Plug 
into the equation of the ellipsoid:
Complete the square:
Then the intersection is such that
which resembles the equation of a circle, and suggests a parameterization is polar-like coordinates. Let
(Attached is a plot of the two surfaces and the intersection; red for the positive root 
, blue for the negative)
