GRAAD/GRADE 8 OPWARMING 8/WARM-UP 8

1. ‘n Kers van 25 cm lank brand teen ‘n tempo van 5 cm per uur. Watter persentasie van die oorspronklike kers is oor nadat dit vir 2 uur gebrand het?A candle 25 cm tall burns at the rate of 5 cm per hour. What percent of the original candle is left after it has burned for 2 hours? _________

2. Indien ‘n muntstuk opgeskiet word vir 17 maal, wat is die waarskynlikheid dat die aantal koppe gelyk sal wees aan die aantal sterte?If a coin is flipped 17 times, what is the probability that the number of heads will equal the number of tails? _________

3. Twee vierkante, elkeen met ‘n oppervlakte van 25 vierkante eenhede, word langs mekaar geplaas om ‘n reghoek te vorm. Wat is die omtrek van die reghoek?Two squares, each with an area of 25 square units, are placed side-by-side to form a rectangle. What is the perimeter of the rectangle? _________

4. Watter persentasie van die eerste 50 positiewe heelgetalle bevat geen onewe syfers nie?What percent of the first 50 positive integers contain no odd digits? _________

5. Indien dit 24 sekondes neem om ‘n “Tweet” te skryf en 8 sekondes neem om dit te stuur, wat is die grootste aantal “Tweets” wat geskryf en gestuur kan word in 6 minute?If it takes 24 seconds to write a Tweet and 8 seconds to send it, what is the greatest number of Tweets that can be written and sent in 6 minutes?

_________6. Vir watter positiewe heelgetal n is 2n+3n+4n=nn?

For what positive integer n is 2n+3n+4n=nn? _________7. Die som van die lengtes van die kante van ‘n kubus is 24 cm. Wat is

die volume van die kubus?The sum of the lengths of the edges of a cube is 24 cm. What is the volume of the cube? _________

8. In ‘n driehoek met hoeke a, b en c grade is die gemiddelde van b en c gelyk aan a. Wat is die waarde van a?In a triangle with angles measuring a, b and c degrees, the mean of b and c is a. What is the value of a? _________

9. In die xy-vlak sny lyne a en b by punt (5;-2), en lyne b en c sny by punt (-3;3). Wat is die helling van lyn b? Druk jou antwoord as ‘n gewone breuk uit.In the xy-plane, lines a and b intersect at point (5;-2), and lines b and c intersect at point (-3;3). What is the slope of line b? Express your answer as a common fraction. _________

10. Hoeveel driehoeke van enige grootte is daar in die figuur?How many triangles of any size are contained in this figure? _________