If $A: B = 3: 4$,$B: C = 4: 5$,and $C: D = 5: 6$,then $A: D$ will be

Sachin is younger than Rahul by $4$ years. If their ages are in the respective ratio of $7:9$,how old (in years) is Sachin?

The sum of three numbers is $98$. If the ratio of the first to the second is $2:3$ and that of the second to the third is $5:8$,then the second number is:

If two numbers are in the ratio $2:3$ and the ratio becomes $3:4$ when $8$ is added to both the numbers,then the sum of the two numbers is

The number of students in three classes are in the ratio $2:3:4$. If $12$ students are increased in each class,this ratio changes to $8:11:14$. The total number of students in the three classes in the beginning was:

If Rs. $872$ is divided into three parts,proportional to $\frac{1}{2}: \frac{2}{3}: \frac{3}{4},$ then the first part is