Given: 3 tailors stitch a PPE suit in 45 hours Formula used: M1 × H1/W1 = M2 × H2/W2, where, M is number of workers, H is number of hours and W is work done Calculation: Let required number of hours be ‘H” According to question: 3 × 45 × 1/1 = 15 × H × 1/8 ⇒ H = 9 × 8 = 72 hours