Problem: the area of a square field is 24200 sq m . how long will a lady take to cross the field diagonally at the rate of 6.6 km / hr ?
Rationale: "explanatory answer step 1 : compute the length of the diagonal of the square let ' a ' meters be the length of a side of the square field . therefore , its area = a 2 square meters . - - - ( 1 ) the length of the diagonal ' d ' of a square whose side is ' a ' meters = √ 2 a - - - ( 2 ) from ( 1 ) and ( 2 ) , we can deduce that the square of the diagonal = d 2 = 2 a 2 = 2 ( area of the square ) or d = √ 2 * area meters . d = √ 2 ∗ 24200 = 48400 = 220 m . step 2 : compute the time taken to cross the field the time taken to cross a distance of 220 meters while traveling at 6.6 kmph = 220 m / 6.6 kmph convert unit of speed from kmph to m / min 1 km = 1000 meters and 1 hour = 60 minutes . so , 6.6 kmph = 6.6 ∗ 1000 / 60 m / min = 110 m / min ∴ time taken = 220 / 110 = 2 minutes choice c"
annotated_formula: divide(24200, multiply(6.6, const_1000))