Average of 4 consecutive multiples of 5 is 30. What is the largest? MCQ with Answer and Explanation

Numbers 5k,5k+5,5k+10,5k+15. Average 5k+7.5=30. 5k=22.5? 5(k +1.5)=30 wait: sum 20k +30 =120, 20k=90, k=4.5? Use integers: numbers 20,25,30,35. Average 27.5 no. Adjust: for average 30, numbers 20 25 30 35 avg 27.5. Change to 25 30 35 40 avg 32.5 no. Standard valid: numbers x-7.5 to x+7.5 but use 20,25,30,35 avg=27.5. To fit, use different.