A bag contains 5 blacks, 4 white and x red marble. If the probability of picking a red marble is $\tfrac{2}{5}$, find the value of x 

The response of 160 pupils in a school asked to indicate their favorite subjects is given in the bar chart above. What percentage of the pupils has English and Health Education as their favorite subjects?

For what value of n is ^{n + 1}C₃ = 4(ⁿC₃)?

In triangle XYZ $\angle XYZ={{15}^{o}},\angle XZY={{45}^{o}}$and $\left| XY \right|=7cm$.Find $\left| YZ \right|$

In the diagram above, find the value of x

PQ and RS are two parallel lines. If the coordinate P, Q, R, S are (1,q), (3,2), (3,4),(5,2q) respectively . Find the value of q

In the diagram above, PQ = 10cm, PS = 8cm and $\angle PSR$ is 60^o. While SRQ is a right angle. Find SR

If the locus of the points which are equidistant from P and Q meets line PQ at point N, then PN equals 

PQRSTW  is a regular hexagon and OS intersect RT at V. Calculate $\angle TVS$