If doubling a number and adding 20 to the result gives the same answer as multiplying the number by 8 and taking away 4 from the product, the number is :
A
2
B
3
C
4
D
6
Correct Answer: 4
"ধরি, সংখ্যাটি x তাহলে, 2x + 20 = 8x – 4 ⇒ 8x – 4 = 2x + 20 ⇒ 8x – 2x = 20 + 4 ⇒6x = 24 ∴ x = 4"