Find the direction of v as a positive angle measured from the x-axis. Round to the nearest degree. v= -8i+15j

Find the value of x for which line a is parallel to line b

Out of $20$ creepy-crawly creatures in a room, $80\%$ are flies and $20\%$ are spiders. if $s\%$ of the total legs belong to spiders, what is $s$?

In a two-digit number the units' digit is 7 more than the tens' digit. the number with digits reversed is three times as large as the sum of the original number and the two digits. find the number.