Elain can knit 4 scarves in 20 days. In 40 days, she would knit 8 scarves.
If Mario can knit 2 more scarves than she can in 40 days, then he can knit 10 scarves.
Divide the days by the scarves, to find that Elain knits one scarf in 5 days, and Mario knits one scarf in 4 days.
Hope this helped, and dm(?) me if you want me to elaborate!
