For the following questions answer them individually
What is the least number which when increased by 13 is divisible by each of 42, 36 and 45 ?
When 1 is added to to $$\frac{13}{15}$$ th part of $$\frac{7}{8}$$ then it is equal to n-th part of $$\frac{13}{7}$$ Then n=
The ratio of the present age of a man and his wife is 4:3 and 4 years hence the ratio of their ages will be 9:7 If the ratio of their ages at the time of their marriage was 13:9, how many years ago were they married ?