Questions

Hydrogen is the common element in all acids.

Mumbai has been ranked the world's second most densely populated city with 31,700 people per sq km, by the World Economic Forum (WEF) citing UN Habitat Data. Bangladesh's capital Dhaka topped the list with 44,500 people per sq km. Rajasthan's Kota has been ranked the world's seventh most densely populated city with 12,100 people per sq km.

Sulphur is an yellow element that stinks when burned.

From first figure : each fig has the value of 20 => It has inside 4 figures => Each individual figure has the value of '5'

From second => Each Triangle has the value of '1' (bcoz it contains two in each)

From third => Figure star has the value of '4'

Then in fourth => 4 + 1 + 15 = 20