QUestion: {Please don't provide any web link or certified answer for the below question. Please provide only experts answer. Answer the following with the help of diagram and examples. Explain the optical illusion in Maths for making a working model on it.

QUestion:{Please don't provide any web link or certified answer for the below question. Please provide only experts answer. Answer the following with the help of diagram and examples.

Explain the optical illusion in Maths for making a working model on it.

Q.71. A streamer goes downstream from one point to another In 9 hours. It covers the same distance upstream in 11 hours. If the speed of stream be 3 km/hr then the distance between the points is

(1) 288 km

(2) 297 km

(3) 270 km

(4) 279 km

$67.Thelengthofthelargestpolethatcanbeplacedinaroomofdimension\phantom{\rule{0ex}{0ex}}12m\times 9m\times 8mis\phantom{\rule{0ex}{0ex}}\left(1\right)36m\left(2\right)144m\left(3\right)17m\left(4\right)28m\phantom{\rule{0ex}{0ex}}\phantom{\rule{0ex}{0ex}}68.Thesumoffirst32oddnaturalnumberis\phantom{\rule{0ex}{0ex}}\left(1\right)1156\left(2\right)961\left(3\right)1024\left(4\right)1089$