Question 836295
3:5:7 means we have 3x, 5x and 7x of Cement, gravel, and sand where x is some number


Since "If 5 tons of cement are available", we know {{{3x = 5}}} and {{{x = 5/3}}}


So {{{5x=5(5/3)=25/3}}} tons of gravel can be used


and {{{7x=7(5/3)=35/3}}} tons of sand can be used


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In total, {{{5/3+25/3+35/3=(5+25+35)/3 = 65/3}}} tons of mix can be made


Note: {{{65/3}}} is an improper fraction and {{{65/3 = 21&2/3}}} (the number on the right side is a mixed number)