72 is 4/9 of a number. What is that number?

Please attempt the above question timed by clicking on the digital timer below:

Hours:Minutes:Seconds

00:00:00

Now, please click on “Reveal Technique” below to reveal the three (3) second “winning edge technique” leading to the correct answer:

Technique © :
Step 1. Multiply 72 by 9/4 [inverse of 4/9 given in question]

72 x 9/4

Step 2. Cancel 72 with 4 and multiply out the resulting number by 9

18 x 9 =162.

Answer: 162.

Time allowed: 30 seconds Time taken using the technique: 3 seconds

__Time saved = 27 seconds [9/10__^{th} of time allowed by examiner]
Now attempt the Practice question given below to check whether you can arrive at the correct answer within three seconds:

WORK SHEET – Practice question
21 is 3/7 of a number. What is that number?

Step 1.Step 2.
Now click on “Reveal” to check your answer is correct:

Answer: 49