Question

20,40,100,?,820 what is the answer for this

Answer 1

Answer

• 280

Given

• 20 , 40 , 100 , ? , 820

To Find

• ?

Solution

$\bf 20\ \underbrace{\;\;\;}_{20} 40\ \underbrace{\;\;\;}_{60} 100\ \underbrace{\;\;\;}_{?-100} ?\ \underbrace{\;\;\;}_{820-?} 820$

Note : The numbers which are written under the under brace are difference b/w upper and lower numbers .

$\bf 20\ \underbrace{\;\;\;}_{20} 40\ \underbrace{\;\;\;}_{20 \times 3} 100\ \underbrace{\;\;\;}_{So,(60 \times 3)=?-100} ?\ \underbrace{\;\;\;}_{820-?} 820$

So ,

60 × 3 = ? - 100

⇒ 180 = ? - 100

⇒ 180 + 100 = ?

⇒ 280 = ?

⇒ ? = 280

Verification

Now take fourth difference .

⇒ 180 × 3 = 820 - ?

⇒ ? = 820 - 540

⇒ ? = 280

Hence verified

Answer 2

Answer:

(*3)-20....(100*3)-20=280