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If 21x = 79x, what is the value of x?




Similar Math Riddles

Find a 9-digit number, which you will gradually round off starting with units, then tenth, hundred etc., until you get to the last numeral, which you do not round off. The rounding alternates (up, down, up ...). After rounding off 8 times, the final number is 500000000. The original number is commensurable by 6 and 7, all the numbers from 1 to 9 are used, and after rounding four times the sum of the not rounded numerals equals 24.

Asked by Neha on 01 Sep 2021


A large water tank has two inlet pipes (a large one and a small one) and one outlet pipe. It takes 3 hours to fill the tank with the large inlet pipe. On the other hand, it takes 6 hours to fill the tank with the small inlet pipe. The outlet pipe allows the full tank to be emptied in 9 hours.

What fraction of the tank (initially empty) will be filled in 0.64 hours if all three pipes are in operation? Give your answer to two decimal places (e.g., 0.25, 0.5, or 0.75).

Asked by Neha on 08 Jan 2026

John was running from 40 thieves. John has got 3 gold boxes which weigh as 4kg, 2kg, and 1kg respectively. A witty man asked John to stay with him for seven days in exchange for 1kg gold per day. John needs to stay there for seven days and also do not want to give the witty man any advance. How can John pay for his seven days stay?

Asked by Neha on 14 Jul 2023


Rectify the following equality 101 - 102 = 1 by moving just one digit.

Mathematical Signs Magic

Asked by Neha on 08 Mar 2021

A little girl goes to the store and buys one dozen eggs. As she is going home, all but three break. How many eggs are left unbroken?

Asked by Neha on 02 Mar 2022

A rain drop fell from one leaf to another leaf and lost 1/4th of its volume. It then fell to another leaf and lost 1/5th of the volume. It again fell on another leaf and lost 1/5th of the volume.



This process kept repeating till it fell on the last leaf losing 1/75th of its volume.



Can you calculate the total percentage of loss from the initial volume when the drop has fallen to the last leaf accurate up to two decimal places?

Asked by Neha on 16 Feb 2021


What's a single-digit number with no value?

Asked by Neha on 06 Aug 2025

Three brothers Jacob, John, and James live in Mexico City. The product of the ages of these brothers is 175. Jacob and John are twins. How old is James?

Asked by Neha on 02 Sep 2024

Baseball bat and ball cost $100. If the bat cost $99 more than the ball, what is the cost of each?

Asked by Neha on 23 May 2021


A newspaper is supposed to have 60 pages.Pages 14 and 21 are missing from the newspaper.

Can you tell me , Which other pages won't be there as well ?

Asked by Neha on 07 Feb 2023

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There is a cryptic organization called Cicada 3301 that posts challenging puzzles online, possibly to recruit codebreakers and linguists.