What's the only room from which no one can enter or leave

Can you solve the below algebraic mathematical equation?

(J+O+I+N+T)3 = JOINT

In a science lab, a petri dish hosts a healthy colony of yeast for an experiment. Now every minute, all the yeast cells divide into two. At noon, there was just a single cell of yeast and at 1:22, the Petri dish was half full. Can you calculate when the dish will be full of yeast?

The sum of a mother, her baby and her dog's weight is 170 Kg. How much does the baby weigh if the mother weighs 100 kg more than the combined weight of the baby and the dog, and the dog weighs 60 per cent less than the baby?

Which part of London exists in France as well ?

Where do you go to learn how to make ice cream?

Four people need to cross a rickety bridge at night. Unfortunately, they have only one torch and the bridge is too dangerous to cross without one. The bridge is only strong enough to support two people at a time. Not all people take the same time to cross the bridge. Times for each person: 1 min, 2 mins, 7 mins and 10 mins. What is the shortest time needed for all four of them to cross the bridge?

I know a nine-letter word having only one vowel.
Do you ?

There is a place where if I stand up straight, I will still be considered sideways.

What has 13 hearts but no other organs?