Math Riddles

Answer: When he gets on the subway it is 6 stops away from the end of the line (end of the track). So when it reaches this point it begins to work backwards. So when it goes back one stop he has traveled 7 stops but is only 5 away from where he began.

Answer: He is with the mother.

If you do the math: (baby's age) + 21 + 6 = 5 * (baby's age + 6)
(baby's age) + 27 = 30 + 5 * (baby's age)
-3 = 4 * (baby's age)
-3/4 = baby's age
The baby will be born in 9 months.

Answer: 95. Dividing by 1/2 is the same as multiplying by 2. So, 40 * 2 + 15 = 95.

Answer: They just have to flip it twice. They call the first toss either heads or tails, then the next toss they automatically pick the opposite (ie if one man calls heads on the first flip, he automatically picks tails on the second and vice versa). If they both win one toss (a tie) out of the two, they just have to repeat until one of them wins both tosses.

Answer: If they are round the manhole covers cannot slip into the hole if the hole is slightly smaller than the cover, but if they are square the hole would have to be about 50 percent of the area of the cover to stop the cover from falling into the hole (diagonally).