Four numbers, when arranged in ascending order, are w, x, y and z. The average of the smallest three numbers is 18, while the average of the largest three was 22. What is the range of the data?
How much quantity (in kg) of wheat costing Rs 84 per kg must be mixed with 81 kg of wheat costing Rs 60 per kg so that on selling the mixture at Rs 75.9 per kg, there is a gain of 15%?
Three triangles are marked out of a bigger triangle at the three vertices such that each side of each of the smaller triangles is one-fourth as long as each corresponding side of the bigger triangle. The ratio of the area of the three small triangles taken together to that of the rest of the bigger triangle is