This is the 2013 Grade 8 Math Challenge Elimination Level Questions with Answers – Part 2. Questions in the previous years can be accessed on the **Past Tests** page and all questions can be found in the** All Posts** page.

26.) What should be subtracted from to get

27.) If , what is

28.) A storage battery discharges at a rate which is proportional to the storage. If the charge is reduced by 25% of its original value at the end of 3 days, how long will it take to reduce the charge to 10% of its original charge?

29.) If *r* and *s* are the roots of the equation , what is

30.) The value of* *C varies directly with x and the square of y and inversely with the cube of *z*. If each *x, y* and *z* are to be increased by 50%, what would be the effect on the value of *C*?

31.) If the sum of the reciprocals of the roots of the equation is what is *k*?

32.) A long wire is cut into three smaller pieces in the ratio of 7 : 3 : 2. If the shortest piece 16 cm, what is the area of the largest rectangle that can be created using the longest piece?

33.) Find the value of *x* in the equation

34.) Find the largest integer *n* such that 1 + 2 + 3 + · · · + *n* < 500.

35.) A boat takes 2/3 as much time to travel downstream as to return. If the rate of the river’s current is 8 kph, what is the rate of the boat in still water?

36.) If what is

37.) Find the value(s) of *x* so that *x*,* 2x* + 7 and 10*x *− 7 will form a geometric sequence.

38.) If , what is *x*? (Note: Ten terms of )

39.) In let *D* be the point on side *BC *such that *AB *= *AC *= *BD*. If what is

40.) Let be an arithmetic sequence. If and , what is

41.) What is the fourth root of

42.) The operation is defined by What is

43.) Triangle *ABC *is isosceles with *AB *= *AC*. Let *D *be the foot of the altitude from *A *on *BC*, and let *E* be the point on side AC such that DE bisects If what is

44.) Let be a non-constant arithmetic sequence. If and form a geometric sequence, what is the common ratio of this geometric sequence?

45.) What is the greatest integer less than or equal to

46.) If and , what is

47.) If , find

48.) Simplify:

49.) Solve for *x*:

50.) If find the value of

Answer key:

26.)

27.)

28.) 10.8 days or

29.) 7

30.) no effect.

31.) 3

32.) 196 cm²

33.) 2012

34.) 31

35.) 40 kph

36.) 0.525557943

37.) 7 and

38.) 11

39.) 57°

40.) 3

41.)

42.) 16096

43.) 44°

44.)

45.) 13

46.) 12

47.) 18

48.) 2

49.) 3

50.)

View Part 1 here: 2013 Grade 8 Math Challenge Elimination Level Questions with Answers – Part 1