Question Number 57549 by Joseph2002 last updated on 07/Apr/19
$${first}\:{question}. \\ $$$${solve}\:{for}\:{x}:\:\underset{{k}=\mathrm{1}} {\overset{\mathrm{5}} {\sum}}{kx}=\mathrm{60} \\ $$
Commented by math1967 last updated on 07/Apr/19
$${x}+\mathrm{2}{x}+\mathrm{3}{x}+\mathrm{4}{x}+\mathrm{5}{x}=\mathrm{60} \\ $$$$\Rightarrow\mathrm{15}{x}=\mathrm{60}\therefore{x}=\mathrm{4} \\ $$