Question

Set up equations and solve them to find the unknown numbers in the following cases: 
(a) Add 4 to eight times a number; you get 60. 
(b) One-fifth of a number minus 4 gives 3. 
(c) If I take three-fourths of a number and add 3 to it, I get 21. 
(d) When I subtracted 11 from twice a number, the result was 15. 
(e) Munna subtracts thrice the number of notebooks he has from 50, he finds the result to be 8. 
(f) Ibenhal thinks of a number. If she adds 19 to it and divides the sum by 5, she will get 8.
(g) Anwar thinks of a number.If he takes away 7 from \(\frac{5}{2}\) of the number,the result is 23.

Answer 1

(a) Let the number be x
According to the question,  8x+4=60
\(\Rightarrow\)  8x+4=60
\(\Rightarrow\) 8x=56
\(\Rightarrow\) \(x=\frac{56}{8}\)

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(b) Let the number be y  
According to the question,  \(\frac{y}{5}-4=3\)

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(c) Let the number be z  
According to the question, \(\frac{3}{4}z+3=21\)

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(d) Let the number be x  According to the question,
2x-11=15

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 (e) Let the number be m  
According to the question,  50-3m=8

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(f) Let the number be n,  According to the question,  \(\frac{n+19}{5}=8\)

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(g) Let the number be x  According to the question,  \(\frac{5}{2}x-7=\frac{11}{2}\)