The task is to generate the correct answer for a given math problem.

[Q]: Problem: the product of two successive numbers is 4160 . which is the smaller of the two numbers ?
[A]: 64


[Q]: Problem: meena wrote all the numbers from 1 to 29,999 inclusive . how many digits did she write in total ?
[A]: 138,889


[Q]: Problem: if the length and breadth of a rectangular room are each increased by 1 m , then the area of floor is increased by 21 sq . m . if the length is creased by 1 m and breadth is decreased by 1 m , then the area is decreased by 5 sq . m . the perimeter of the floor is :
[A]:
40', 'd ) 49', 'e ) 38'