 <translate> They spent $8 each on cheeseburgers and milkshakes because 3 + 5 = 8. They spent $16 on these items in total because 2 x 8 = 16. They spent $24 on their meal because 16 + 8 = 24. They had $30 to start because 24 / .8 = 30. His cousin had $10 because 30 - 20 = 10.
Therefore, the answer is 10. <yor> Wọ́n ná dọ́là mẹ́jọ lẹ́nì kọ̀ọ̀kan lórí àwọn búrẹ́dì tí wọ́n fi wàrà ṣe àti àwọn ọtí tí wọ́n fi wàrà ṣe nítorí pé mẹ́ta àti márùn-ún bára mu mẹ́jọ. Wọ́n ná $16 lórí àwọn nǹkan wọ̀nyí ní àpapọ̀ nítorí pé 2 x 8 = 16. Wọ́n ná $24 lórí oúnjẹ wọn nítorí pé 16 + 8 = 24. Wọ́n ní $30 láti bẹ̀rẹ̀ nítorí pé 24 /.8 = 30. Ọmọ àbúrò rẹ̀ ní $10 nítorí pé 30 - 20 = 10. Nítorí náà, ìdáhùn náà ni 10. 