Respuesta :

Answer:

31/40 has to be added to the sum of 5/8 and 8/5 to get 3​.

Step-by-step explanation:

Solve this equation:  5/8 + 8/5 + f = 3, where f is the number that has to be added to the sum of 5/8 and 8/5.

The LCD of 5/8 and 8/5 is 40; thus, 5/8 + 8/5 = 25/40 + 64/40 = 89/40.

Then 89/40 + f = 120/40 (where 120/40 is equivalent to 3).

Subtracting 89/40 from both sides yields the desired result:

f = (120 - 89)/40 = 31/40

31/40 has to be added to the sum of 5/8 and 8/5 to get 3​.

Answer:

[tex]\frac{31}{40}[/tex]

Step-by-step explanation:

let the unknown be x

[tex]\frac{5}{8} + \frac{8}{5} + x =3[/tex]

[tex]\frac{25+64+40x}{40} = 3[/tex]

cross multiply

25 + 64 + 40x = 3 × 40

89 + 40x = 120

collect like terms

40x = 120 - 89

40x = 31

divide both sides by 40

x = [tex]\frac{31}{40}[/tex]

therefore, [tex]\frac{31}{40}[/tex] has to be added to the sum of 5/8 and 8/5 to get 3