A low land, 48m long and 31.5 m broad is raised to 6.5 dm. For this, earth is removed from a cuboidal hole, 27 m long and 18.2 m broad, dug by the side of the land. The depth of the hole will be?

Question

A man rows 12 km in 5 hrs against
the stream, the speed of current being 4 kmph. What time will be taken by him to row 15 km with the stream?

The length of two parallel chords of a circle of radius 5 cm are 6 cm and 8 cm in the same side of the centre. The distance between them is?
Pls help***

Answer 1

If the depth is x dm, then we have
48*31.5*6.5 = 27*18.2*x

If his speed is x in still water then
12/(x-4) = 5
Use that x to evaluate
15/(x+4)

Draw a diagram. If you draw a radius perpendicular to the chords, you bisect them. You then have two 3-4-5 triangles (the radius of 5 is the hypotenuse)

So, now it's easy to see how far apart they are.